Amanaote 12 mm Dimeter Eyelet Hole Hollow Punch Bags Wad Material Circle Cutting Tool The punch hole diameter:12 mm. Hollow Round Hole Punch Tool. Drop forged and heat treated Knurled bodies for a secure grip Perfect for making holes in leather, rubber, vinyl, paper, gaskets, and many other soft materials. For punch hole and install snap fasteners, press studs, rivet, grommet, etc.