Gaosi Tools Set of 6 Pcs Craft Tool Die Punch .3.0-4.0-5.0-6.0-7.0-8.0mm Materials:Durable solid metal construction made by #45 steel. niversal setter base with 6 widths: 3-4-5-6-7-8mm For punch hole and install snap fasteners, press studs, rivet, grommet, etc Easy to use, just place punch in position and strike firmly with hammer or mallet Great for making clean holes in gaskets, leather, plastic, rubber and other soft materials