Fangrui Product Details The [1/4-inch Core Hex Handle Self Centered Hinge Practice Is Made Of High-quality Materials For Doors And , But Can Also Be Used For Drilling Aluminum, Copper, Stainless Steel, And Other Metal Door And Window Hinges. For Drilling In Hinges, Hardware, Or Any Time You Need To Accurately Locate Holes. The Self Centered Drill Tip Of The Is Customized And Can Be Opened More Accurately With Less Eccentricity To Help With Correct And Center Seated Hinges. Other: Has A Flat Bottom. The Universal 1/4inch Hex Shank Is Designed For A Wide Range Of Applications. It Must Be A Center Flight Hole In Sizes. The Self Centered Change Door Drill Bit Set Includes 9 Bits And 1 Hex Key. The Bit Models Are 5/64inch, 7/64inch, 7/64inch, 9/64inch, 9/64inch, 11/64inch, 5mm, 13/64inch, 1/4inch. A Complete Set Of Custom Matches, Comprehensive, Comprehensive, Just In Case. The Brightly Colored Case Is Pleasant And Easy To Recognize. The Drill Bit Has A Design And Careful Production, Making It A Good Choice For Diy Enthusias