Product Material: Our Automatic Center Punches Are Made From Well-Machined Aluminum Alloy Or Steel (Housing) And Have A Deeply Knurled Surface To Prevent Slipping And Provide More Precise Handling And Control. Is Made Of Chrome Vanadium Steel,Enough For Hundreds Of Blows!Range Use: High Speed Metal Center Punches That Actually Work In Wood, Glass, Canvas, Steel, Plastic, Leather Materials, Aluminum, Brass, Copper And Other Metal Materials.User'S Manual: Use Your Heavy Head To Mark The Center Of A Hole You Want To Make. Press Firmly On The Handle And Push It Towards The Punches. After The Punch Has Been Pushed Back Into The Rod For A Short Time, The Powerful Spring Forcefully Ejects The Punch.Emergency Situations: Not Only Is It Suitable For Wood And Metal, But It Can Break The Glass Of Glass Car, Just Use It In The Corner Of A Window And It Will Crack And Fall. You Can Directly Push And Escape.Size Specifications: Auto Center Punch Length 13/5.1 Inches. Gold And Silver (Color) (With Plastic Handles): Steel Case, Weighs About 72G. Black: Steel Case, Weighs About 65G. Blue: Aluminum Alloy Case, Weighs About 33G. The Plastic Handles Can Be Fitted And Removed.