Rack- A- Tiers' 18- in x 3/4- in Topman auger bit features a lower spur, ideal for drilling in wood that contains nails, and has a quick change hex shank drill bit. Length: 18-in; Diameter: 3/4-in. Quick change hex shank drill bit (7/16-in). Suggested drill RPM: 600 Max. Do not use in areas where screws/coarse thread are embedded. Durable - The spiral structure and solid build of the core make it almost impossible for these auger bits to break, even when drilling through nails. Long Lasting - Made of high-carbon steel (S55C), these auger bits go through a special heat-treating process for increased strength and durability. Smooth - The feed screw, cutting edge, and lowered spur ensure the holes you drill are clean and consistent. Versatile - Perfect for any job that involves drilling holes in wood.