Check on your plumbing system with this CHERNE 3 in. Rubber Test Ball Plug. Featuring an inflatable design, it easily fits through sanitary tees, test tees, floor drains and other hard-to-access pipe openings. Made of natural rubber, it has excellent expansion and a great seal in round and out-of-round pipe. This plug is ideal for testing DWV plumbing systems at pressures up to 13 psi or with 30 ft. of head pressure. Color: Black.