PRECISE POSITIONING: No moving, the sawdust will automatically discharge from the top of the hole on both sides, the drill bit will not be blocked. 7 DIFFERENT SIZE: Come with hinge screw sizes most common 5/64, 7/64, 9/64, 11/64, 13/64, 5mm, 1/4. BONUS: Come with automatic center punch . Marks the workpiece with a dimple, creating a starting point that prevents screws and drill bits from getting lost. EASY TO REPLACE: Different hardness wood, need different center drill bit, just disassemble the screw and replace the bit. EASY TO INSTALL: Unique design and perfect impact effect. Applicable for door hinge installation. Easy to use and install, quick change bits that load and release with one hand.