Specifications: Four piece set includes bits for drilling pilot holes for screw sizes #6,#8,#10 and #12. Special designed steel counter sleeve countersinks or counter bores pilot hole. Adjustable counter sleeve depth with allen wrench. Standard hex shank is quick change compatible. Drill and countersink for wood screws without changing bits. Drilling length can be adjusted for various length screws simply by loosening and tightening the setscrew. Type: Drill Bit Set Color: Black Quantity: 4 Pcs Material: HSS Drill 4241 Black Chamfer Drill Body Material: Steel #45 Usage: for Carbon Steel, Thin Iron Plate, Insulating Plate, PVC Board, Wood 6# Size: 2.38mm/0.09" (Approx.) 8# Size: 2.78mm/0.11" (Approx.) 10# Size: 3.175mm/0.12" (Approx.) 12# Size: 3.56mm/0.14" (Approx.) Hex Shank Diameter: 6.35mm/0.25" (Approx.) Notes: Due to the light and screen setting difference, the items color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 x Drill Bit Set(4 Pcs) 1 x Hex Shank