This set was designed for punching holes in steel, brass, stainless steel and blue tempered shim stock. It is advised not to exceed .025" thickness in steel or brass and .010" thickness in stainless and blue tempered. 

Shop - Aid's versatile Shim Punch Set contains the following sizes: 1/8", 3/16" , 1/4", 5/16" , 3/8", 7/16", 1/2", 5/8" , 3/4"