This is an excellent tool for copying odd angles for mitering purpose (angles you find in any house with supposedly square room corners), and can be used for inside angles to 70° and outside angles to 290°.
No calculations are necessary — as you position the guide to match the desired angle, the internal gear automatically aligns the integral steel rudder to bisect the angle. To transfer the half angle, simply move the guide to the miter saw and align the blade parallel with the rudder.
Suitable for inside and outside angles, it can also be used as a layout gauge to mark angles for handsaw cuts.
Made of stable, glass-fiber-reinforced nylon, with a steel rudder. Measures about 10-1/2" overall; rudder is 1-7/8" long by 3/4" high.
Made in Sweden, it is a great time saver for general woodworking.