Waterway Plastics Part# 310-1750 (310-1750B)  Specs OD on the inlet/outlet ports is approximately 3"  Fits select Waterway Pumps, check your manual to ensure proper fit.  The outside diameter on the inlet/outlet ports of this wet end is approximately 3" which fits Waterway Union #400-5570(NOT INCLUDED) or #400-5670(NOT INCLUDED).  This is a complete wet end which includes: the volute housing, pump seal kit, impeller, volute faceplate, volute faceplate O-ring, drain plug and cover screws.