The thick edge is useful as a saw guide. It can be used directly with the saw against the square for cross cuts or angled cuts using the etched protractor scale. It can be used indirectly as well, using the scribing notches to create a saw cut line for rip cuts. Designed to make easy rafter pitch or slope calculations, this handy angle square is also suitable for use as a protractor, combination square and depth adjustment on table saws. The square tool is marked with inches and degrees with cast markings that wont rub off. Easy to read and easy to use.Features:, This aluminum rafter angle square boasts a solid aluminum body with CNC machined edges for greater accuracy and durability for any job or worksiteFor roofs, solar panel supports, stairs, cabinets trim work and many other layout projects. The rafter scales are laid out mathematically to avoid time consuming calculationsEZ-Read is a high-contrast, non-glare finish that scatters ambient light so the only thing you see are our clear, crisp, laser-etched graduations.Can be used as a protractor, line scriber, saw guide and tri/meter square and a ruler, multi-functionalSpecification:, Type: Rafter Square, Blade Length: 7"" , Base Length: 7-1/8"", Graduation: 1/8""Graduation (Degrees): 1.00, Material: Aluminum, 0-90° hypotenuse, 1-30 top cuts, 0-12 in. right angle side"