EOPE Triplex High Pressure Power Washer Pump 4.7 GPM 3600 PSI 1" Hollow Shaft fits Cat General AR 4.76 GPM 3600 PSI Triplex High Pressure Washer Pump replaces Cat General AR The plunger on this pump is ceramic, increasing resistance to pitting and wear. 1" Hollow Shaft Pump fits GX 340 11HP GX 390 13 HP Engine Forged Brass manifold provides high strength and corrosion resistance Thermal relief valve, easy start valve & pressure relief valve