Malco SL-2 Snap Lock Punch Join sheet metal, duct and pipe sections economically. Punches raise a louvered shaped projection on metal ege for locking into rolled edge of sheet or piece to be joined Punch impression spaced 3/8" from edge of metal, pieces snap together and are fastened securely Compound handle leverage for maximum ease of operation, nickel plate and black oxide finish Also used to crimp end caps on gutter