
Evolution Aqua Pressure Pipe Ball Valves
At Cotswold Koi we understand The importance of pipe work, mistakes made in pipework are one of the most common we come across and can be very costly and hard to change at a later date.
There are three main types of pipe work used on koi ponds:
- Metric Pressure Pipe
- Imperial Pressure Pipe
- Black waste pipe
The use of anything other than pressure pipe and fittings for both gravity and pressure lines is risky, the last thing you want is your bottom drain line leaking after all your hard work building your pond and is only a cost saving exercise, The added security and peace of mind that Pressure Pipe brings is well worth the extra cost. Unfortunately the use of pressure pipe and fittings in the past has simply been too expensive for the majority of Koi keepers, despite it being the preferred choice. here at Cotswold Koi we are looking to bring you a full range of pipe fittings for every occasion.
we are happy to provide assistance, should you need it, please Contact Us if you need assistance in choosing the right pipe work for your project.
£17.09 – £121.49Price range: £17.09 through £121.49 inc. VAT Select options This product has multiple variants. The options may be chosen on the product page

Evolution Aqua Surge Waste Assembly Elbow
Evolution Aqua Surge Waste Assembly Elbow
This is a a genuine Evolution Aqua Surge Waste Assembly Elbow . This directly screws into the waste assembly. This Evolution Aqua Surge Threaded Elbow For Waste Assembly is a 1″ thread to a 1″ plain hose tail.

Female Threaded Hose Tail
Female Threaded Hose Tail
Has 1.5″ female BSP Thread (Internally) / fits in a 50mm black waste Solvent Weld Sockets (Externally) on the Threaded End and excepts 2″ (50mm) Flexible pipe on the hose tail end.
The choice of which type of pipework to use has always been a dilemma.
At Cotswold Koi we understand The importance of pipe work, mistakes made in pipework are one of the most common we come across and can be very costly and hard to change at a later date.
There are three main types of pipe work used on koi ponds:
- metric Pressure Pipe
- imperial Pressure Pipe
- black waste pipe
The use of anything other than pressure pipe and fittings for both gravity and pressure lines is risky, the last thing you want is your bottom drain line leaking after all your hard work building your pond and is only a cost saving exercise, The added security and peace of mind that Pressure Pipe brings is well worth the extra cost. Unfortunately the use of pressure pipe and fittings in the past has simply been too expensive for the majority of Koi keepers, despite it being the preferred choice. here at Cotswold Koi we are looking to bring you a full range of pipe fittings for every occasion.
we are happy to provide assistance, should you need it, please Contact Us if you need assistance in choosing the right pipe work for your project.

Flexi Pipe 90 Degree Barbed Joiner
Flexi Pipe 90 Degree Barbed Joiner
The Flexi Pipe 90 Degree Barbed Joiner are perfect for making a nice and tidy job of going round a corner joining two bits of pipe together.
These are available in 3 different sizes 1″, 1.25″ and 1.5″.
At Cotswold Koi we understand the importance of pipe work, mistakes made in pipework are one of the most common we come across and can be very costly and hard to change at a later date.
The use of anything other than pressure pipe and fittings for both gravity and pressure lines is risky, the last thing you want is your bottom drain line leaking after all your hard work building your pond and is only a cost saving exercise, The added security and peace of mind that Pressure Pipe brings is well worth the extra cost. Unfortunately, the use of pressure pipe and fittings in the past has simply been too expensive for the majority of Koi keepers, despite it being the preferred choice. here at Cotswold Koi, we are looking to bring you a full range of pipe fittings for every occasion.
we are happy to provide assistance, should you need it, please Contact Us if you need assistance in choosing the right pipe work for your project.
£2.69 – £4.49Price range: £2.69 through £4.49 inc. VAT Select options This product has multiple variants. The options may be chosen on the product page

Flexi Pipe Straight Barbed Joiner
Flexi Pipe Straight Barbed Joiner
The Flexi Pipe Straight Barbed Joiner are perfect for joining long pipe runs together or joining two small bits of pipe together.
These are available in 3 different sizes 1″, 1.25″ and 1.5″.
At Cotswold Koi we understand The importance of pipe work, mistakes made in pipework are one of the most common we come across and can be very costly and hard to change at a later date.
The use of anything other than pressure pipe and fittings for both gravity and pressure lines is risky, the last thing you want is your bottom drain line leaking after all your hard work building your pond and is only a cost saving exercise, The added security and peace of mind that Pressure Pipe brings is well worth the extra cost. Unfortunately the use of pressure pipe and fittings in the past has simply been too expensive for the majority of Koi keepers, despite it being the preferred choice. here at Cotswold Koi we are looking to bring you a full range of pipe fittings for every occasion.
we are happy to provide assistance, should you need it, please Contact Us if you need assistance in choosing the right pipe work for your project.
£1.79 – £2.69Price range: £1.79 through £2.69 inc. VAT Select options This product has multiple variants. The options may be chosen on the product page

Flexi Pipe Tee Barbed Joiner
Flexi Pipe Tee Barbed Joiner
The Flexi Pipe Tee Barbed Joiner are perfect for making a nice and tidy job when needing to flow water in multiple directions.
These are available in 3 different sizes 1″, 1.25″ and 1.5″.
At Cotswold Koi we understand the importance of pipe work, mistakes made in pipework are one of the most common we come across and can be very costly and hard to change at a later date.
The use of anything other than pressure pipe and fittings for both gravity and pressure lines is risky, the last thing you want is your bottom drain line leaking after all your hard work building your pond and is only a cost saving exercise, The added security and peace of mind that Pressure Pipe brings is well worth the extra cost. Unfortunately, the use of pressure pipe and fittings in the past has simply been too expensive for the majority of Koi keepers, despite it being the preferred choice. here at Cotswold Koi, we are looking to bring you a full range of pipe fittings for every occasion.
we are happy to provide assistance, should you need it, please Contact Us if you need assistance in choosing the right pipe work for your project.
£2.69 – £4.49Price range: £2.69 through £4.49 inc. VAT Select options This product has multiple variants. The options may be chosen on the product page

Flexible Heavy Duty Hose Imperial (Solvent Weld)
Flexible Heavy Duty Hose Imperial
- Easy to lay out thanks to the flexible, UV-resistant material
- Excellent pressure-resistance to 6 bar
- Glues into fittings
*note this flexi pipe is designed to be glued into Imperial pressure pipe fittings
£5.27 – £236.37Price range: £5.27 through £236.37 inc. VAT Select options This product has multiple variants. The options may be chosen on the product page

Flexible Hose Compression Fittings
Flexible Hose Compression Fittings
Flexible Hose Compression Fittings means no more difficult seals using hose clips! These Polypropylene Compression fittings assure a fast and secure fix. The flexible rubber seal adapts to the shape of the hose and works with both thin and thick walled hose.
Available in 1.25″ and 1.5″
£4.94 – £6.48Price range: £4.94 through £6.48 inc. VAT Select options This product has multiple variants. The options may be chosen on the product page

Floating Surface Pond Skimmer With Stainless Basket
Floating Surface Pond Skimmer With Stainless Basket
AquaForte Floating surface skimmer with Stainless basket (300mm). The base and floating parts are made of ABS. Can be used without basket when connected directly with a pre-filter like an UltraSieve. Read more

Gold Label One Shot Sealant
Gold Label Underwater Pond and Aquarium One Shot Sealant:
Gold Label One Shot underwater sealant is ideal for pond and aquarium repairs due its remarkable ability to instantly repair and bond surfaces even while submerged in water. It is easy to use and there is no need to purchase or use a silicone gun. There is no need to remove fish from the water when using Gold Label sealer, it is solvent free and isocyanate free. This high-quality, heavy-duty sealant is perfect for sticking together a wide variety of materials including, various forms of rubber, vinyl, plastic, ceramic, concrete, wood and much more. This makes Gold Label sealer the best product for pond repair work such as mending pond liner. Read more
Available in Black 80ml foil tubes with trigger nozzle (no silicone gun required)
£11.69 inc. VAT Select options This product has multiple variants. The options may be chosen on the product page

Gold Label Pond Paint Black
Gold Label Pond Paint Black
This unique paint is designed to effectively seal and re-paint the concrete lining of your pond. It works using only 2 coats (on smooth surfaces) without needing primer, and as it is water based can be applied to damp surfaces. This means it is also less toxic than traditional pond paints. It has coverage of 6-8 m2 which also means with 2 coats used (on smooth rendered concrete) it is far more cost effective than the typical pond paints out there. With a second coat application time of 6-48 hours and such ease of application, professional pond builders are choosing Gold Label Pond Paint every time! It comes in a variety of colours and sizes, is easy to mix and apply, and dries after 6-8 hours (full cure 3-7 days). The paint also works on other surfaces such as: blocks, brick, tiles, fibreglass and plastic. It should last approximately 5-10 years, giving you a fresh look to your water tight pond for years to come. Read more
Key Points:
- No Primer Needed
- Works on damp surfaces
- Easy to apply with brush, roller or spray.
- Water based, therefore easier to clean & less toxic.
- 2 coats only (on smooth surfaces)
- Quicker pond refill than single pack paints
- Coverage of 6-8 m2 per litre
- Comes in recyclable packaging
£58.49 – £181.79Price range: £58.49 through £181.79 inc. VAT Select options This product has multiple variants. The options may be chosen on the product page

Gold Label Pond Paint Clear
Gold Label Pond Paint Clear
This unique paint is designed to effectively seal and re-paint the concrete lining of your pond. It works using only 2 coats (on smooth surfaces) without needing primer, and as it is water based can be applied to damp surfaces. This means it is also less toxic than traditional pond paints. It has coverage of 6-8 m2 which also means with 2 coats used (on smooth rendered concrete) it is far more cost effective than the typical pond paints out there. With a second coat application time of 6-48 hours and such ease of application, professional pond builders are choosing Gold Label Pond Paint every time! It comes in a variety of colours and sizes, is easy to mix and apply, and dries after 6-8 hours (full cure 3-7 days). The paint also works on other surfaces such as: blocks, brick, tiles, fibreglass and plastic. It should last approximately 5-10 years, giving you a fresh look to your water tight pond for years to come. Read more
Key Points:
- No Primer Needed
- Works on damp surfaces
- Easy to apply with brush, roller or spray.
- Water based, therefore easier to clean & less toxic.
- 2 coats only (on smooth surfaces)
- Quicker pond refill than single pack paints
- Coverage of 6-8 m2 per litre
- Comes in recyclable packaging
£58.49 – £181.79Price range: £58.49 through £181.79 inc. VAT Select options This product has multiple variants. The options may be chosen on the product page

Griffon ABS Solvent Weld Glue
Griffon ABS Solvent Weld Glue
The Griffon ABS Solvent Weld Glue is For joining pipes, sockets and fittings with interference fit in pressure and drainage systems. With special pipe brush for quick and easy application. Suitable for diameters ≤ 160 mm. Max. 10 bar (PN 10). Maximal tolerances 0.3 mm diametrical clearance / 0.2 mm press fit. Suitable for e.g. pipe systems conforming to EN 1455 and ISO15493 (ABS). Read more
Directions for use
- Cut pipes square, chamfer edges and deburr.
- Clean surfaces with Griffon Cleaner and Cleaner Cloth.
- Apply adhesive rapidly and evenly all around (4-6x) on both surfaces (pipe thickly, socket thinly).
- Assemble joint immediately.
- Remove excess adhesive.
- Do not load the joint mechanically for the first 10 minutes.
- Close packaging immediately after use.

Griffon Pipe Cleaner
Griffon Pipe Cleaner
Griffon Pipe Cleaner is a perfect product to clean and degrease your pipe and fittings ready for application. This product is also for cleaning up your tools and will also remove uncured adhesive residue. Read more
This product is available in two different sizes 125ml and 500ml.
£8.99 – £17.09Price range: £8.99 through £17.09 inc. VAT Select options This product has multiple variants. The options may be chosen on the product page

Griffon Uni-100 Solvent Weld Hard Pipe Glue
Griffon Uni-100 Solvent Weld Hard Pipe Glue
Griffon Uni-100 Solvent Weld Hard Pipe Glue, suited for hard PVC pipes and valves in both pressure and drainage. Griffon Uni 100 has gap filling capabilities and is also suited for roof gutters. Complete product information is available on demand. Pressure filling capacity max. 0,2 mm. Gap filling capacity max. 0,8 mm. Read more
Available in 250ml

Hose Clips
Hose Clips
The Hose Clips our perfect for using in conjunction with the black flexible hose. These are easy to tighten or loosen and available in five different sizes.
At Cotswold Koi we understand The importance of pipe work, mistakes made in pipework are one of the most common we come across and can be very costly and hard to change at a later date.
The use of anything other than pressure pipe and fittings for both gravity and pressure lines is risky, the last thing you want is your bottom drain line leaking after all your hard work building your pond and is only a cost saving exercise, The added security and peace of mind that Pressure Pipe brings is well worth the extra cost. Unfortunately the use of pressure pipe and fittings in the past has simply been too expensive for the majority of Koi keepers, despite it being the preferred choice. here at Cotswold Koi we are looking to bring you a full range of pipe fittings for every occasion.
we are happy to provide assistance, should you need it, please Contact Us if you need assistance in choosing the right pipe work for your project.
Available size:
- 2″ ( Stainless Jubilee) to fit 2″ pipe
- 1.75″ (Black) to fit 1.5″ pipe
- 1.5″ (Red) to fit 1.25″ pipe
- 1.25 (Orange) to fit 1″ pipe
- 1″ (Yellow) to fit 3/4″ pipe
£0.89 – £2.24Price range: £0.89 through £2.24 inc. VAT Select options This product has multiple variants. The options may be chosen on the product page

Impermax Aqua Liquid Pond Paint
Impermax Aqua Liquid Pond Paint
Impermax is a single component, high performance waterproofing material, based on Polyurethane, certified according to EEC Directive 98/83/CE, and which can be in direct contact with drinking water for human consumption. It can easily be applied on different kinds of surfaces used in hydraulic infrastructures such as concrete, mortar, ceramics, fibreglass, reinforced polyester, etc. Read more
Curing time: 4-6 hours in the summer, 12-24 hours. Apply at least 3 to 4 layers to obtain a membrane thickness of 1.5 to 1.9 mm (2 kilo per m²).
It is recommended to use Humidity Primer in most situations.
£39.59 inc. VAT Select options This product has multiple variants. The options may be chosen on the product page

Impermax Geomax Geotextiel – 30cm x 100m
Impermax Geomax Geotextiel – 30cm x 100m
Geomax Geotextiel reinforcement. A special nonwoven, made of synthetic fibre, specially developed for use in conjunction with Impermax (and its elasticity). This is optimally suitable for places (eg corners, gaps, floor drains) where increased protection is necessary. This cloth minimizes the effect of self-distribution of the product and thus ensures that a corresponding thickness is reached quickly.
Main applications: IMPERMAX internal layer to protect against damage caused by corners, sharp objects, edges, etc to reduce the effect of self-distribution, for example, when processing steep / vertical surfaces as protection from below, when IMPERMAX on uneven surfaces is processed. Read more
Geomax is available in small width (30 cm), ideal to treat wall/floor areas, and when preparing areas before waterproofing.

Impermax Humidity Primer 5kg
Impermax Humidity Primer
It is not recommended to apply Impermax Aqua membrane directly on surfaces which may contain moisture or on damp surfaces, or humidity content, either on the surface or trapped underneath.
Humidity creates two important problems in treatments:
- Lack of adhesion.
- The appearance of blisters in the surface of the finished membrane (due to the vapour pressure generated as the area is exposed to sunlight, which creates bubbles and deforms the elastic material).
In case of damp surfaces, or if there is suspicion of humidity, it is imperative to pre-treat the area with Impermax Humidity Primer.
It is recommended to use Humidity Primer in most situations. Impermax can be applied even in cases of low temperatures (< 5ºC) and high relative humidity’s, obtaining very short cure times in combination with our PUR Cat additive. Read more
Usage:
5 kg is sufficient for approx. 16.6 m²

Impermax Paintchlore
AquaForte Impermax Paintchlore
Impermax Paintchlore Transparent (chlorine resistant) can be painted over an existing Impermax layer to make this chlorine resistant, or you want to repair a leak to other existing (swimming pool) tiles or (swimming pool) film.
Since the normal Impermax Liquid film is not chlorine resistant. Impermax 2 kg per m² general description: economical and easy to use, gives your pond a seamless, continuous membrane that completely matches the surface. Outstanding mechanical and chemical properties. Certified according to EEC directive 98/83/CE, which means it can even come into contact with drinking water for human consumption. This membrane can even be easily used on places that other systems find hard to reach. Impermax can be applied at low temperatures and in relatively damp conditions. Doesn’t need to be mixed and no special primer is required. The product consists of one component. Read more
It is recommended that in most use cases that the Humidity Primer is used as a base. Consumption: 2 kg per m².

Impermax PU Primer 4 kg
Impermax PU Primer 4 kg
The PU primer serves as a primer for very smooth and non-porous surfaces such as ceramics, tiles, metal, plastic, etc. and thus ensures better adhesion between the existing surface and Impermax. If the waterproof surface is very smooth and non-porous (e.g. ceramic, tile, aluminium, etc.) it can happen that the high cohesion of this product means that Impermax does not adhere immediately. First treat the surface with PU primer, this ensures better adhesion between the existing surface and Impermax. Read more
Consumption:
0.2 kg / per m²
4 kg are sufficient for approx. 20 m²
The quantity of PU Primer should be approx., 200 to 300 grams per square meter.

Impermax Pur Cat 1 kg
Impermax Pur Cat 1 kg
Impermax Pur Cat needs to be added to impermax and the curing time between coats can be reduced to 2 to 3 hours. Pur Cat Impermax Accelerant must also be used when installing at temperatures below 5°C. Read more
Application method:
- 1kg of Pur Cat Impermax Accelerant should be added and mixed per 25kg of Impermax.

Impermax Solvent 4 kg
Impermax Solvent 4 kg
Impermax Solvent is ideal in situations when porous materials such as cementing, masonry etc… it is recommended to apply a first layer of Impermax diluted with the Rayston solvent in a proportion of 5 to 10%. When the porous materials are saturated, it is then possible to apply the liquid membrane normally. Ideally, this first application should be done at a rate of 0.5 kg / m2 This product can also be used to dilute Impermax (5 to 10%) for airless application. Read more

Kockney Koi Double Union Ball Valve
The Kockney Koi Double Union Pressure Pipe Ball Valve
The Kockney Koi Double Union Pressure Pipe Ball Valves are available in two sizes 4″ Imperial Pressure and 110mm Metric Pressure. These sturdy ball valves are designed to fit standard pressure pipe and can be utilised for numerous applications. The Kockney Koi Ball Valves are well suited for reducing pump flow rates, isolating pipework runs or opening and closing drain outlets. Thanks to the Double Union connections, equipment such as pumps can easily be removed by turning off the valve and unscrewing it from the system.
4″ Pressure Pipe Ball Valve
- Overall length 290mm
- Overall Width 195mm
- Bottom to top of handle 260mm
110mm Metric Pressure Pipe Ball Valve
- Overall length 290mm
- Overall Width 195mm
- Bottom to top of handle 260mm
At Cotswold Koi we understand The importance of pipe work, mistakes made in pipework are one of the most common we come across and can be very costly and hard to change at a later date.
There are three main types of pipe work used on koi ponds:
- Metric Pressure Pipe
- Imperial Pressure Pipe
- Black waste pipe
The use of anything other than pressure pipe and fittings for both gravity and pressure lines is risky, the last thing you want is your bottom drain line leaking after all your hard work building your pond and is only a cost saving exercise, The added security and peace of mind that Pressure Pipe brings is well worth the extra cost. Unfortunately the use of pressure pipe and fittings in the past has simply been too expensive for the majority of Koi keepers, despite it being the preferred choice. here at Cotswold Koi we are looking to bring you a full range of pipe fittings for every occasion.
we are happy to provide assistance, should you need it, please Contact Us if you need assistance in choosing the right pipe work for your project.
£70.19 inc. VAT Select options This product has multiple variants. The options may be chosen on the product page

Oase 1.5″ Inch Flow regulator with Hose Tails
Oase 1.5″ Inch Flow regulator with Hose Tails
The Oase flow regulator 1 ½ “for step less adjustment of the water flow rate has 2 universal step hose nozzles for the connection of 1” to 1 ½ “hoses.
For adjustment of water flow rates with 2 stepped hose adapters 1″ – ½”
At Cotswold Koi we understand The importance of pipe work, mistakes made in pipework are one of the most common we come across and can be very costly and hard to change at a later date.
There are three main types of pipe work used on koi ponds:
- Metric Pressure Pipe
- Imperial Pressure Pipe
- Black waste pipe
The use of anything other than pressure pipe and fittings for both gravity and pressure lines is risky, the last thing you want is your bottom drain line leaking after all your hard work building your pond and is only a cost saving exercise, The added security and peace of mind that Pressure Pipe brings is well worth the extra cost. Unfortunately the use of pressure pipe and fittings in the past has simply been too expensive for the majority of Koi keepers, despite it being the preferred choice. here at Cotswold Koi we are looking to bring you a full range of pipe fittings for every occasion.
we are happy to provide assistance, should you need it, please Contact Us if you need assistance in choosing the right pipe work for your project.

Oase Aqua Skim 20 (Standing)
Oase Aqua Skim
The OASE AquaSkim 20 keeps a water surface of up to 20 m² clean and is an ideal addition to the AquaMax Eco Premium models 4000-8000. Its skimmer basket has a diameter of 126 mm. It can be easily adapted to the pond depth thanks to the two-part telescopic tube, which is infinitely adjustable in height from 320 to 800 mm. The skimmer compensates for water level differences of up to 100 mm. The filter basket volume is 1.4 L. The skimmer lets through dirt particles up to 10 mm in size. Thanks to the 350 mm base, the AquaSkim 20 can be fixed to the pond floor with stones that are particularly stable. The small pipe diameter of 80 mm also ensures less air content and thus prevents the skimmer, which has a connection with a universal stepped hose nozzle from ¾ “to 1½”. Read more
Characteristics:
- The result is clearly improved water quality and viewing depth through direct suction removal of pollutants on the surface
- Base with large surface receptacle shell for rocks as ballast
- Oase Aqua Skim 20 – ideal for use on the AquaMax Eco Premium 4000-8000
- Aqua Skim Gravity with high quality DN 160 / 110 adapter for easy integration in DN 110 line systems
- Easy maintenance with easily accessible coarse debris basket
- Debris basket can also be taken out from a distance via grip hooks
- Ideal combination with AquaMax Eco Premium filter and watercourse pumps
- Powerful suction cleaning of pond surfaces up to 20 m²

Oase Aqua Skim 40 (Standing)
Oase Aqua Skim 40
The OASE AquaSkim 40 keeps the water surface of up to 40 m² clean and is an ideal addition to the AquaMax Eco Premium models 8000-16000 and Twin 20/30000. The skimmer basket has a diameter of 170 mm. It can be easily adapted to the pond depth thanks to the two-part telescopic tube, which is infinitely height-adjustable from 300 to 800 mm. The skimmer compensates for water level differences of up to 120 mm. The filter basket volume is 1.4 l. The skimmer lets through dirt particles up to 10 mm in size. Thanks to the 350 mm base, the AquaSkim 40 can be fixed to the pond floor with stones that are particularly stable. The small pipe diameter of 80 mm also ensures less air content and thus prevents the skimmer, which has a connection with a universal stepped hose nozzle from ¾ “to 1½”. Read more
Characteristics:
- The result is clearly improved water quality and viewing depth through direct suction removal of pollutants on the surface
- Base with large surface receptacle shell for rocks as ballast
- AquaSkim 20 – ideal for use on the AquaMax Eco Premium 4000-8000
- AquaSkim Gravity with high quality DN 160 / 110 adapter for easy integration in DN 110 line systems
- Easy maintenance with easily accessible coarse debris basket
- Debris basket can also be taken out from a distance via grip hooks
- Ideal combination with AquaMax Eco Premium filter and watercourse pumps
- Powerful suction cleaning of pond surfaces up to 40 m²

Oase AquaSkim Gravity
Oase AquaSkim Gravity
The AquaSkim offers powerful suction of up to 40 m2 pond surface and adapts to water level changes of up to 120 mm – making it an effective addition to the entire filter system. It is worth the effort: significantly better water quality and visibility depth through direct dirt extraction from the surface. It has an easily removable debris basket that collects larger floating particles such as leaves. Read more
Characteristics:
- The result is clearly improved water quality and viewing depth through direct suction removal of pollutants on the surface
- Base with large surface receptacle shell for rocks as ballast
- Easy maintenance with easily accessible coarse debris basket
- Debris basket can also be taken out from a distance via grip hooks
- Ideal combination with AquaMax Eco Premium filter and watercourse pumps
- Powerful suction cleaning of pond surfaces up to 40 m2
- With high quality DN 160 / 110 adapter for easy integration in DN 110 line systems
