Functions as a framing square, try square, miter square, protractor, saw guide, stair gauge and out-of-square corner angle finder. It's constructed of heavy-gauge aluminum alloy and includes the Layout Bar for use in determining out-of-square corners. Black graduations for easier reading; matte finish to prevent glare. Includes: Swanson Blue Book of Rafter Length and Roof Construction, and layout bar and hardware.