The 40mm Push-Fit Soil Internal Rubber Boss Adaptor is a specialized elastomer fitting designed to reduce and adapt a standard boss socket (found on 110mm soil branches, strap-on bosses, or boss pipes) down to accept a 40mm waste pipe.
 
It inserts directly into the open entry of an internal or external soil boss. The outer flexible ribbed fins compress against the inside wall of the boss socket to form a tight, air- and watertight friction seal. The inner aperture accepts the plain spigot end of a 40mm plastic waste pipe (from kitchen sinks, washing machines, or bath discharges), holding it securely via a push-fit ring seal mechanism without needing solvent cement or special tools.
 
Manufactured from synthetic EPDM rubber in compliance with UK plumbing standards (BS EN 1329-1 / BS 4514), this flexible adaptor absorbs pipe vibration and natural thermal movement along the waste line while preventing foul sewer gases from backing up into the property.