"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. Shaft Diameter in. 24mm, Application Pressure washer pump, GPM 4 1/2, HP 12 1/2 electric, 16 gas, Fuel Type Electric, gas, Max. PSI 4,000. Brand AR Pumps Belt drive"