Simpson Cleaning 90037 Triplex Plunger Horizontal Pressure Washer Replacement Pump 8.7GA12 3400 PSI @ 2.5 GPM with Brass Head and PowerBoost Technology Direct drive horizontal pump, forged brass head, black anodized aluminum crankcase, 3/4shaft, thermal relief valve, SAE gas engine flange, threaded M22 pump outlet connection Universal to fit most brands/models. Pump oil capacity: 8.0 fluid ounce Precision polished ceramic coated pistons for improved seal life, dual oversized radial ball bearings for better wear and friction resistance, and integrated unloader with easy-start feature Pre-sealed and pre-filled with oil in the pump and oversized site glass does away with the need for a dipstick Patent Pending PowerBoost Technology to enhance cleaning performance. Has an Adjustable Unloader