Stens 030-458 Pressure Washer Pump. Bore Size 0.512". 4 Gallons Per Minute. GHP 16.4. RPM 3400. EP Series Pump. Size 1. SAE J609B. Solid ceramic plungers with dual guide systems. New dual diameter plunger guide, optimized outlet valves and dual lip oil seals. Shaft is flanged for direct couple to gas engines. Replaces OEM General Pump EP1313G8.