Punches : 7/8"(22.2mm) 1-11/32"(34.1) Punching range: punch the hole on the mild steel or aluminum studs 1mm. Features: • Unique design accommodates punching all known shape, easily punches "H" studs without damaging flanges. • High-leverage design permit punching holes in aluminum stud and mild steel (up to 20-gauge) with minimum effort. Learn More