Polypipe PVC Underground Drain Lowback 'P' Trap Spigot 110mm is used to trap or collect any unwanted debris and prevent it from entering the drainage system. This then stops any blockages deeper within the system. The P trap also stops any harmful and unpleasant gases from passing back through the trap. It has a spigot outlet and a socket inlet connection. It is an alternative to traditional clay drainage systems. It features a simple seal and snap cap system for strong and durable joints.