Features STEEL ALLOY MATERIAL: This drill bit is made of premium alloy steel, wear and impact resistant, and has a long lifespan. FAST CHIP REMOVAL: A spiral groove with a central drill bit will efficiently prevent the accumulation of retained rock cuttings, quickly discharge debris from the hole, and increase drilling efficiency. EASY CARRYING: The drill bit set is lightweight and portable for easy use, do not take up much space, use at will! LIMIT ADJUSTABLE: The drill bit's premium punching efficiency and ability not to pierce wall are both attributes of its adjustable limit. Use as needed. WIDE APPLICATION: This drill bit can be used for countersinking and drilling soft metal, fiberboard, wood, plastic, and screws made of aluminum alloy, among other materials. Specification: Item Type: Counterbore Drill Bit Material: Alloy Steel Color: Silver Specification: Approx. 3.5 x 10mm / 0.14 x 0.39in Application: Used for countersinking and tapping wood, plastic, soft metal, fiberboard, aluminum alloy screws, etc. Package List: 1 x Counterbore Drill Bit  1 x Wrench  1 x Hex Wrench  1 x Set Screw  1 x Storage Box  Package List 1 x Counterbore Drill Bit 1 x Wrench 1 x Hex Wrench 1 x Set Screw 1 x Storage Box