Metal Stud Punch 1-11/32" (22.2 MM) Diameter. Punch Up Through 20 Gauge (0.9 MM) Steel Studs In One Stroke. Aluminum Head Provides Strength With Minimum Weight, Reducing Operator Fatigue. Contoured Handle Design Gives Better Operator Leverage and Makes It Possible to Punch In Tight Places. Self-Stripping Design Eliminates Punch Hang-Ups. Automatically Centers Holes On Standard Studs. Conversion Kit Available to Up Grade Early Models From 24 Gauge to 20 Gauge Maximum Capacity.