Adjustable Snap Lock Punch, Punch Type Sheet Metal Punch, Application Creating Locking Tabs in Light Sheet Metals, Creates Hole Size 1/4 to 5/8 in, Overall Length 8 in, Maximum Jaw Opening 5/8 in, Maximum Material Thickness Aluminum: 0.035 in, Jaw Opening Type Spring Return, Features Compound Leverage Produces 7 to 1 Mechanical Advantage, Ergonomic Redline Handles Won'T Wear You Down, Ideal for Crimping Gutter End Caps in Place or Creating Your Locking Tabs for Sheet Metal Duct Corners