The 7 Rafter Square has a stronger frame and is the most versatile rafter angle square. Scribe notches from 1 - 6 allow you to easily and accurately rip lumber. A 1 cutout in the rafter square helps prop pipe allowing you to cut it more easily on the job site. A reinforced frame gives you more durability on the job site while high visibility laser etched markings make the square easier to read.