Complete hinge drill bit set with 7 sizes: 5/64', 7/64', 9/64' (two bits), 11/64', 13/64', 5 mm, and 1/4', includes a hex key for quick setup and adjustments. materials: drill core made of speed steel and an aluminum alloy shell; hardness, rust resistant, sturdy and durable to support reliable, longlasting performance. Ideal for door and window hinges: specially designed to create screw holes for hinges with a selfcentering feature that securely holds position for precise drilling. Precision you can trust: automatic centering minimizes shifting and misaligned holes, delivering consistent hole accuracy. Practical applications: suitable for installing interior and exterior doors, mounting window hinges, and general cabinet or furniture hinge installations where precise hinge holes are required. Practical notes: compatible with standard hinge screw holes; includes a hex key for convenient adjustments and maintenance.