Knuckle bends are used to create tight, neat 90 degree bends in a waste pipe system. They have a tighter radius than the standard swept bends.This fitting is available in 32mm, 40mm and 50mm size options, with 50mm only available in grey.This push fit waste system is manufactured in the UK to BS EN 1451 and is British Standard kitemarked.When making a push fit joint, cut the pipe square and remove any burrs, push the pipe into the fitting as far as it will go and then withdraw it by approximately 10mm to allow for any expansion. The joint can be taken apart again if required, but always check that the O ring has not been dislodged from its housing groove in the fitting as this will cause the joint to leak.Click here to read our guide that explains the key differences between push fit and solvent weld waste systems.