It combines the functions of a combination, try and framing square, and can be used to make basic measurements, as well as a saw guide for 45° and 90° cuts. It can also be used as a protractor, allowing the measurement of angles and pitches. This makes light and fast work of cutting wall shoulders (bird beaks) or rafter ends. The adjustable protractor arm can be locked in place with the brass screw, a useful feature when making repetitive cuts.
Also known as a layout, angle, rafter or speed square, it is the go-to product for many carpenters. It is designed to provide a quick and accurate way to mark out many building projects and is widely used when constructing roof rafters.