This is a high quality hollow punch kit, which allow you to work on leather , gasket material, rubber, soft metal, thin foil, brass, and screen material. This is a great set for getting the job done and done right. This set includes six pieces ranging from 3/8 inch to 3/4inch. Place the hollow punch in the material you want the hole in, and then hit the top of the tube with a hammer or mallet. This will create a hole allowing you to do what is needed. Each one of these tube is heat treated and made with high carbon steel. Made with a high carbon steel Includes: 3/8" 7/16" 1/2" 9/16" 5/8" 3/4" Heat treated Knurled bodies for a secure grip Precision ground flutes and cutting edges Clean punches Accurate holes Easy to use