As a saw guide, stair layout tool or rafter tool, Johnson's 7 inch rafter square will help you get the job done accurately and easily. It features Johnson's unique Structo-Cast molded frame that is both lightweight and durable as well as permanent molded graduations for making quick and easy measurements. Use the scribe notches for marking and ripping lumber, and handy markers that measure 2x4 board dimensions. And you'll always find this square quickly in your toolbox thanks to its fluorescent, easy-to-see color.