The Swanson® Speed® Square was first developed by company founder Albert Swanson in 1925. This innovative tool combines 5 tools into 1: 1. Try Square, 2. Miter Square, 3. Saw Guide, 4. Line Scriber, & 5. Protractor. The Speed® Square is die-cast for durability and accuracy. Made of heavy-gauge aerospace aluminum alloy, it is built to last. Black-filled gradations stand out against a matte finish for easy reading. The Speed® Square includes the Swanson® Blue Book of Rafter Length and Roof Construction and also features markings for using the Swanson® One-Number® Method of rafter layout. The Swanson® Speed® Square is our most popular product and remains the most trusted square of its kind. Look for the Diamond® cutout for genuine Swanson® products.