This Wood Drill Bit Kit pre-drills holes and countersinks even wood, reducing the risk of splitting the panel, and giving every screw, nail or bolt a beautiful appearance as it appears flush with the surface of the furniture , and can be covered well with wooden caps. Range: 7 Countersink 4-spline bits with 7 Hex adjustable depth stop collars, compatible with screw sizes: 5, 6, 7, 8, 9, 10, 12 - bit sizes: 1 or 8 inch (3.18 mm), 9 or 64 inch (3.58 mm), 5 or 32 inch (3.97 mm), 11 or 64inch (4.37 mm), 3 or 16 inch (4.76 mm), 13 or 64 inch (5.15 mm)and 7 or 32 inch (5.56 mm) - Allen key: 3 or 32" diameter. Drill bits are 4241 high speed steel, black parts are 45 steel All bits have sharp points and are able to hold heat and pressure without breaking or shattering and damaging the panel for a perfect finish. Comes with hex key and plastic storage case. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.