SHORTE 20swg (1.0mm) Button Punch Snap Lock Rollformer is a 9 station machine and is principally used in the HVAC industry for joining sheet metal at right angles on straight and curved duct sections. The female ‘Lock’ is formed in one pass and the flange, complete with the punched louvers, is formed on the auxiliary side of the machine. Simply snap the flange into the female section. There is no knocking over of the edges as with the Pittsburgh Lock. This machine has 415v, 3 phase electrics. (Ref:329).