The Swanson Speed Square is the original rafter square: a framing square, try square, miter square, protractor and saw guide in one tool, in 7 in and 12 in sizes.
Notches spaced at 1/4 and 1/2 in let you run a pencil along the stock to scribe lines. The 7 in rides in an apron, and the 12 in lays out rafters and wide stock.
Swanson Tool Co. has been based in Frankfort, Illinois, since 1925, the year Albert Swanson invented the Speed Square. It still calls itself the inventor of the Speed Square and makes select layout tools in the USA.