40 mm (1.1/2") nominal fittings which accept BS EN 1455-1 and BS EN 1451-1 plastic pipe, and copper pipe to BS EN 12449. The flexibility of the compression ring makes these fittings useful for obsolete and non-standard systems.
The actual size of pipes are approximately 41 mm o.d. x 36 mm i.d. (40 mm)

The spigot end is the same size as the 40mm ABS pipe which can be fitted into a solvent weld socket, elbow or tee.