Set of (2) 2 1/2" Spa Hot Tub Pump Union Waterway T Gasket O.D. 3 1/2" 2 3/8" I.D. 3 1/2" Outside Diameter 2 3/8" Inside Diameter Fits 3" Heater Tube Union Fits Most 3" Spa Heater Tubes Lip 2 7/8" Center to Center