2.5" Union for Side Discharge Waterway Executive 56 Frame 2.5" Inlet Spa Pump # 400-6010 Union fits Waterway Side Discharge Spa pump For 56 Frame Executive 2-1/2" Inlet For 2-1/2" schedule 40PVC Outside thread size = 3 5/8"; Includes O-Ring Unions may not fit other brand pumps. Sold Individually.