This pneumatic test ball plug is designed for blocking sewer flow and conducting sewer air tests. Item: Test Ball Plug Type: Pneumatic Nominal Size: 1-1/2" Min. Dia.: 1.49" Max. Diameter: 1.88" Max. Back Pressure: 50 ft. of Head Required Inflation Pressure: 40 psi Deflated Size: 3.80"L x 1.40"D Material: Rubber For Use In: Blocking Sewer Flow Or Conducting Sewer Air Tests