GEAR REDUCTION, PA B-18, 1"-24 MM Hotsy Pacific Sale! from $338.00 Qty. Add to Cart This item is currently on backorder but you can still purchase it now and we'll ship as soon as more become available. Fits Legacy, Admiral, Bertolini, GP, Interpump, Comet, Udor & Hawk. Engine-to-Pump Drive Units 2.18 to 1 Reduction Ratio (3,675 Eng. RPM = 1,750 Pump RPM) Engine Shaft Size = .0984", 1", 1-1/8" & 3/4" 24 mm Pump x 1" Engine, B18