Polypipe Bottle Anti-Syphon Trap 76mm Seal White is situated on the outlet of an appliance as an integral part of the waste system. It provides a water seal between the waste water pipe and the internal environment of the room. It prevents any foul odours from the drains from re-entering a room. It has a removable bowl to clear any blockages and should only be used on washbasins. This bottle trap features an anti-syphon valve which eliminates negative syphonic pressure and gurgling.