Package IncludesThe hinge drill bit set includes 8 most common hinge screw sizes: 5/64", 7/64", 9/64", 9/64", 11/64", 13/ 64", 1/4", 5mm; 1 x hex key; 8 x spare drill bits (to replace the 8 self-centering drill bits of each size). brass designed.High hardness, rust-proof, solid, durable and superior drilling performance which is a guide to centering the pilot holes needed for the hinges. Reasonable Design Double-sided hole design fast and automatic sawdust discharge of wood from the hole on both sides, no drill blocked, saving your time to remove sawdust. Easy to use and install Different hardness wood, need different self-centering drill bit , you just need to use the hex keys to disassemble the screw and replace the drill with a new one. e perfect joiner for woodworking, mounting hinges on wooden doors, cabinets, windows, etc. Wide UsageApplicable for furniture, kitchens, woodworking, bathroom doors. windows, etc., different hardness wood requires different self-centering drill, and you just need to disassemble the screw and replace the drill with a new one.-7