"This AR Pumps Pressure Washer Pump offers fast changeover, even in the field. Pre-plumbed and pre-tested. Fits 4-bolt engine face plates. Bolts not included use existing bolts from old pump to install new pump. U.S.A. Application Pressure washer pump, Fuel Type Electric, gas, Max. PSI 4,000, GPM 4 1/2, Shaft Diameter in. 24mm, HP 12.5 electric, 16 gas. Pre-plumbed and pre-tested Fits 4-bolt engine face plates Belt drive"