The Johnson Level 12" Aluminum Angle Rafter Square features a solid aluminum body with CNC machined edges for greater accuracy and durability. Permanent graduations and numbers are easy to read. Thick edge is useful as a saw guide. Scribe notches starting at 1-3/4" transfer outside increments from pivot point. Low-glare, protective powder coated finish. The 12" body spans wider boards simplifying layout and measurements.