Nail Eater Extreme 1/2" (12.7 mm) hole diameter. 18" (457.2 mm)overall length. Improved cutting edge provides 30 percent longer life span. Patented new design for improved cutting and cleaner holes. Self-feeding screw point draws bit through wood. Unique patented design cutting angle - smoother starts, reduced cutting loads. Made of super tough, heat-treated steel. Cuts through nails and provides longer life. Shorty bits - for working in tight places, yet still can go through three abutting 2 x 4s.