10-inch diameter, 10.75 & 11.50-inch bolt circles, 2800-3200 RPM stall;Needle Bearing Between Stator and Turbine ; Higher Stall Speed, Quicker Acceleration; Anti-balloon Plate for Added Strength; Furnace Brazed Impeller and Turbine; Fully Balanced and Pressure Tested; Steel Alloy Pump Drive Tube; B&M Quality & Durability;