We are asked this on a daily basis. If you have 40mm pipe (supplied by us), then you would require a 40mm valve. There are many different types of fittings/pipe on the market therefore sizes will differ. All our fittings are compatible with aquatic manufacturers equipment, such as Deltec, Aquamedic etc.

Our pipe size is taken on the outside diameter and the fittings are measured on the inside diameter. Any other questions such as "will this fit my pipe?" is simply guesswork.