The Swanson 7" Speed Square is actually five tools in one: a try square, a miter square, a protractor, a line scriber, and a saw guide. The Speed® Square is constructed of durable heavy-gauge aluminum alloy. Includes markings for Swanson’s One-Number MethodSM of rafter layout, and is packaged with the Swanson® Blue Book of Rafter Length and Roof Construction. Look for the Diamond®.