This machinist square set is used for layout or test square work. Features ul style"margin-top0px; padding-top 5px; padding-bottom 5px;" includes 2" 4" 6" (beams are 1-1/2" 3" 4") made of finest hardened steel designed for precision layout and measurement work squares are true right angles both inside & outside beams and blades are ground and lapped for parallelism length of blade is measured from corner edge of beam to end of blades protective case included