SPEED SQUARE W/BLACK MARKINGS, BLUE BOOK The Swanson SpeedSquare 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 SpeedSquare 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 SwansonBlue Book of Rafter Length and Roof Construction and also features markings for using the Swanson One-Number Method of rafter layout. Look for the Diamond cutout for genuine Swanson products.