PRECISE POSITIONING: No moving, the sawdust will automatically discharge from the top of the hole on both sides, the bit will not get stuck. 7 DIFFERENT SIZE: Comes with hinge screw sizes most common 5/64", 7/64", 9/64", 11/64", 13/64", 5mm, 1/4". BONUS: Come with an automatic center punch. Mark the piece with a dimple, creating a starting point that prevents screws and drill bits from getting lost. EASY TO REPLACE: Wood of different hardness, requires a different centering bit, just disassemble the screw and replace the drill. EASY TO INSTALL: Unique design and perfect striking effect. Applicable for installing door hinges. Easy to use and install, quick change bits that load and release with one hand.