This Patented Metric Speed Square 250mm Square is five tools in one. Its a Try Square, Miter Square, Protractor, Line Scriber and a Saw Guide. This square has indications for the One-Number MethodSM of rafter layout. It also features two separate scales so you can work in either metric or degrees for common and hip valley rafter layouts. Just like the Speed Square, its made of high-grade aluminum alloy. When used as a saw guide, the Speed Square makes truing up a board easy. SpecificationsLength: 250mmProduct Material: Aluminium Features and BenefitsMulti-tool: Try square, mitre square, saw guide, line scriber and protractor0.5cm spaced scribing notchesGraduations included for marking common hip, valley, and jack raftersHeavy-gauge billet aluminum alloy construction is die-cast for increased accuracyHigh-visibility, black graduations with a non-glare, matte finish