The Masterforce door latch mortise tool is used toaccurately marka door latch with a 2-1/4 high x 1 wideguide to help you remove material evenly from doors 1-1/34 inches or 1-3/8 inches thick. Use in tandem with a corner chisel or similar tool. It also features a 1″ chiseled blade on the side to remove material from the strike plate area on the jamb. Made from high impact plastic with a metal marking blade.