The Black Drain Adaptor to Connect 32mm 40mm & 50mm Waste Pipes directly to a surface water drain or depending on the design via a gully trap to the underground drainage system. The adaptor push-fits in to the gully pipe fitting & has markings to cut the opening to the designated pipe size. Simply cut to the required size & push the waste pipe into the opening on the adaptor so that is fully inserted then pull it back slightly to ensure its sealed around the pipe.