Max SN890CH/34 Clipped Head 2-Inch to 3-1/2-Inch Framing Nailer Anti-double fire mechanism (US patent 5597106, UK Patent 2286790) Dial adjustable depth control Easy jam clearance door (Patent pending) Tangle free swivel plug (Added from 2002 production) Lock-out Mechanism - Tool will not fire unless more than three nails are in the magazine