12 inch Aircraft extension high speed steel fracti Fractional straight shank drill bit.3/8 in. x 12 in.Aircraft extension is ideal for applications requiring an extended reach.Black oxide coating resists corrosion.Ideal for drilling in hard to reach areas and for running wires and cable.Constructed of M-2 high speed steel for the best combination of strength, heat resistance and wear resistance.For general use in wood, metal and plastic.Black oxide coating resists corrosion135 degree split point ensures a true start and eliminates bit walking3-5/8 in. twist length