Test drain, vent and waste systems with this Rubber Test Ball Plug. Ideal for DWV plumbing systems, each inflatable test ball can be used with in those systems with pressures up to 13 PSI or with 30 ft. of head pressure. It will seal both round and out-of-round shapes. The steel chain acts as an anchor to prevent the ball plug from falling down line. The natural rubber construction ensures excellent expansion and memory. Color: Black.