Product selling point: The Shank of the stainless steel drill is 1/4'' inch.Suitable for the wood window or door tapping. Fast replacement composite cone, uses drill edged principle. Drilling and tapping, high working efficiency. High hardness, rustproof, solid and durable. Positioning accuracy, will not shift, the chips automatic discharge from either side of the top of the drill hole, don't stick drill. Usage instruction: Please adjust according to the hardness of the wood, if the wood is soft, choose a smaller size; If the wood is hard, you can choose a larger size or corresponding opening tool. Accurate drilling exact pilot holes in cabinet door hinges, door butts, handles, drawer slides, and more. Size: 5/64'': Hole diameter is about 2 mm,Use about 2.2 - 2.8 mm tapping screw 7/64'': Hole diameter is about 2.8 mm,Use about 3 - 3.5 mm tapping screw 9/64'': Hole diameter is about 3.5mm,Use about 4 - 4.5 mm tapping screw 11/64'': Hole diameter is about 4.5mm,Use about 5 - 5.5 mm tapping screw 1.97"/5mm: Hole diameter is about 5mm,Use about 5.5 - 6 mm tapping screw13/64'': Hole diameter is about 5.2mm,Use about 6 - 6.5 mm tapping screw 1/4'': Hole diameter is about 6.35mm,Use about 7 - 7.5 mm tapping screw Please Note: The silver set and black set are the same but only the color.