Triplex High Pressure Washer Pump 3000 psi 6.5 HP 3/4" Shaft fits Cat General AR High-pressure triplex pump 15 Series. 3/4-inch hollow shaft pressure washer pump. Maximum Pressure: 3,000 PSI (206 Bar) Flow Rate: 3.1 GPM Requires: 3,400 RPM and 6.5 HP