This 40mm boss adaptor solvent is made to be installed with 43mm (known as 1 1/2 inch solvent weld) pipe or fittings. If your pipe or existing fittings measure 40mm, or has PP printed on it, then this product is not compatible and you will require 40mm pushfit or compression fittings This listing is for a Pack of 5 Soil pipe boss adaptor for use with a 110mm strap boss to allow a solvent weld pipe to be installed in the boss This solvent weld boss adaptor is secured using solvent weld cement for a permanent and strong installation boss adapter