Irwin Aircraft Extension Aircraft Extension 5/16 in. Dia. x 12 in. L Black Oxide Split Point DriIrwin Aircraft Extension Aircraft Extension 5 16 in. Dia. x 12 in. L Black Oxide Split Point Dri Brand Name: Irwin Sub Brand: Aircraft Extension Diameter: 5 16 in. Overall Length: 12 in. Material: High Speed Steel Product Type: Split Point Drill Bit Shank Type: Straight Shank Number in Package: 1 pc. Packaging Type: Carded Finish: Black Oxide Design: Aircraft Extension Flute Length: 3 3 16 in. Ideal for drilling in hard to reach areas and for running