3/4" grey pvc pressure pipe fittings.

Outside of the pipe and inside of the fitting should be around 27 mm.

Designed to be used with solvent cement for a watertight seal.

Available in many different styles of fittings, please see picture and selection list
BSPF = Female thread
​BSPM = Male thread
Union is a demountable fitting which can be unscrewed in the centre even with the pipe attached