User Guide: * Choose a sutiable size drill bit depend on the woods' hardness level: - If the wood is a soft one, choose a relatively one size smller drill bit; - If the wood is a hard one, choose an exact size or a relatively one size larger drill bit; * Choose a Sutiable Size Drill Bit Depend on the Diameter of the Screw: - 5/64" bit can drill a hole(hole diameter is 2mm) for screws whose diameter is 2.2-2.8mm; - 7/64" bit can drill a hole(hole diameter is 2.8mm) for screws whose diameter is 3-3.5mm; - 9/64" bit can drill a hole(hole diameter is 3.5mm) for screws whose diameter is 4-4.5mm; - 11/64" bit can drill a hole(hole diameter is 4.5mm) for screws whose diameter is 5-5.5mm; - 5mm bit can drill a hole(hole diameter is 5mm) for screws whose diameter is 5.5-6mm; - 13/64" bit can drill a hole(hole diameter is 5.2mm) for screws whose diameter is 6-6.5mm; - 1/4" bit can drill a hole(hole diameter is 6.35mm) for screws whose diameter is 7-7.5mm; * What if the drill bit get stucked: - If the drill bit get stuck and jammed after drilling and you are not able to pull it out, use the L-Shape Wrench to disassemble the drill bit into parts, then you can get the bit out. What You Will Get: 8 x Self Centering Drill Bits 1 x L-Shape Wrench 1 x Black Plastic Case