Quickly and easily punch precision bolt holes in flange gaskets. Select the desired diameter cutting head (1/8 to 2 in standard) or (2 mm to 50 mm metric), mount on handle, position on gasket material, and strike. Patented locking system allows rapid interchange of cutting heads. Unique design punches single diameter holes (bolt holes) as well as dual diameter rings (washers) in one operation. Hardened steel cutting heads stay sharp.