Crafted around a copper-and-aluminum plunger core, this 4300 PSI / 4.4 GPM pressure washer pump gives contractors and serious homeowners an upgrade-grade replacement for 1 in. horizontal shaft engines in the 13-15 HP range. The SAE bolt pattern lines up with horizontal engine pressure washers including Simpson MorFlex models 40224, 40225, 40226 and Santoprene 41182, while an advanced anodizing process delivers a hard protective surface rated for up to 500 hours of continuous use. An integrated oil sight glass lets you read oil levels without breaking the unit down, and the onboard pressure regulator dials output up for tough stripping work or down to a near-idle for soap, rinse, and detail passes. With a 3/4 in. NH garden hose inlet, 3/8 in. quick connect outlet, 4.4 GPM max flow, 3700 PSI recommended working pressure, and 21.49 lb. net weight, the pump pairs with 5 quick-connect nozzles for fast spray-pattern swaps on driveways, siding, fences, and equipment. Designed for cold water only, the unit answers the common worry of whether a high-flow pump will fit common horizontal engines by matching engine orientation, PSI, GPM, shaft diameter, and inlet/outlet connections to leading Pro models without sacrificing flow or maintenance access.