Create locking tabs for resizing rectangular metal duct at the job site. The Malco SL1R Snap Lock Punch raises a louver-shaped projection along the edge of sheet metal that is to be inserted into the rolled lock seam edge of another metal sheet to create a corner connection. The metal pieces snap together and are locked securely. The punch impression is spaced 3/8 in. (9.53 mm) from the metal edge to fit into standard lock seams. A heavy forged cutting jaw and powerful compound handle leverage makes this tool suitable for working in Galvanized steel up to 24 gauge (0.71 mm). Rust resistant nickel plate and black oxide finishes ensure long service life. The SL1R Snap Lock Punch also features ergonomic Redline Handle technology. An Engineered handle opening compliments the natural power stroke of any user's hand and maximizes the powerful 7:1 mechanical advantage of compound-leverage head to handle linkage. Comfortable handle grip contours, a non-slip grip insert, spring handle actuation and a thumb-operated handle latch ensure a natural fit and feel for comfortable one hand operation anywhere on the job.