4GPM, 4000PSI. Recommended for use with engines of 14.5HP. For engines with 1" Shaft. Easily replace your old pump with a pump made ready. Simply remove your old pump and slide this pmr onto the shaft of your gas engine. This pump made ready consists of the pump, a VRT3-310EZ adjustable pressure actuated unloader with a built-in easy start valve, a thermal relief valve to help prevent overheating, along with an inlet filter. All fittings are quick connected.