The Grainger 16X399 is a 16-inch diameter, 3-blade, aluminum propeller for small aircraft. It has a pitch of 9 inches and is designed for engines up to 65 horsepower. The propeller is constructed from heat treated aluminum alloy for strength and durability. It uses a standard 1/4-inch through bolt hole pattern for easy installation. The propeller provides efficient airflow and thrust for light aircraft. With quality construction and materials, the Grainger 16X399 propeller is well-suited for many small piston engine aircraft.