This is a DeWALT 2-1/4" (57,2mm) Self-Feed Wood Bit Model Number DW1638. This Bit is Brand New in Original Packaging. Features and Benefits: *Aggressive Spur Provides Fast Material Penetration. *Optimized Cutting Geometry Provides Longer Bit Life. *Open Tooth Design Allows for More Resharpenings. *7/16" Ball Groove Shank for Quick Change Applications.