Product Information: AR1666 Gearbox - 550 RPM - Hydraulic Diaphragm Pump Medium Pressure 140°F - Max Water Temp New and Improved Gearbox for 5.5-6.5HP Gas Engines Benefits: Eliminates Gas Engine Shaft and Key Wear Easy to Service Runs Cooler for Longer Life Mounts All Medium Pressure Diaphragm Pumps to Gas Engines with 3/4” Shaft * PAYMENT PLANS AVAILABLE AT CHECK-OUT