Irwin Tools 3041021B Speedbor MAX Speed Standard Bit, 1-1/2", 6" Speedbor MAX Speed Bits 6" Standard Length Bits Three cutting spurs for faster, cleaner holes, less breakout and extended drilling life Full screw-point tip allows bit to self-feed for ease of drilling Tapered tri-flute design for faster chip ejection and less binding 1/4" quick-change shank reduces slipping in standard chucks and is compatible with all 1/4" quick-change chucks, including impact drills