Speed Square w/Black Markings, Blue Book, SPEED CLIP 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.
Black-filled gradations stand out against a matte finish for easy reading.
Includes the SwansonBlue Book of Rafter Length and Roof Construction and also features markings for using the Swanson One-Number Method of rafter layout.