11" diameter, 11.4-inch bolt circle, 3500-3800 RPM stall;Needle Bearing Between Stator & Turbine; Higher Stall Speed, Quicker Acceleration; Anti-balloon Plate for Added Strength; Furnace Brazed Impeller & Turbine; Fully Balanced and Pressure Tested; Steel Alloy Pump Drive Tube; B&M Quality & Durability;