Designed for precision measuring & layout angles.  Graduation 1º Dial, 5 min. Vernier.  Hardened stainless steel.  Satin chrome finish on dial face & Vernier for easy reading.  Blade slides over full length, with knurled thumblock.  Protractor head accepts 6" & 12" blades.  Vernier reading in 5 minutes of the arc.  Includes protractor head with magnifier lens, acute angle attachment and base for protractor with ground V and clamp.