Features: Woodworking counterbore hole drill bit set includes five commonly apply sizes of countersink drill bit - #4 (7/64"), #6 (9/64"), #8 (11/64"), #10 (3/16"), #12 (7/32"), a 1/4" hex shank quick replacement bitholder, and a hexwrench. The counter sink drill bit involves two adjust screws that can be moved up or down the shank of the bit to limit how far the drill penetrates into the materials; The adjust counter sleeve depth can be easily modified using the included hexwrench. Crafted from highly speed steel, these tapered drill bit for wood is not easy to break and rusts, providing precisions and performances you can rely on, suitable for various materials. The 1/4inch hex shank magnetic drill bitholder serves as convenient accessory for quickly swapping out countersink drill bit during drilling operations. Clean and Store the drill bit after each use. Specifications: Material:Carbon Steel,Highly Speed Steel Handle Type: 1/4 hexagons handle (6.3mm) Size: 7/64, 9/64, 11/64, 3/16, 7/32 Package Includes: 1Set Countersink Drill Bit note: Please allow 1mm errors due to manual measurement. Due to the difference between different monitors, the picture may not reflect the actual color of the item.