Quickly bore through creosoted and salt treated utility poles. Resists wear, eats through nails and staples. Self feeding screw point draws the bit through the wood. 7/16″ hex shank to fit impact drivers. Available in 18″ overall length.Sizes:37868; 9/16″ Diameter37869; 11/16″ Diameter37870; 13/16″ Diameter37871; 15/16″ DiameterAll Bits have: , 7/16″ Hex Shank Size, 15″ Twist Length, 18″ Overall Length