Since 1947 Johnson Level & Tool has been developing solutions to help professional tradesmen improve their work. Their products are trusted by professionals worldwide to work more accurately, more quickly and more reliably. The thick edge of Johnson Rafter Squares makes them useful as saw guides and for overhanging boards. Our 7" aluminum rafter square comes with continuous scribing notches, ideal for ripping at 3. 1/2" and 5. 1/2"