Put simply, if you own a Miter Saw, you need to own the Starrett 505P-7 Miter Saw Protractor. Forget complex calculations and wasted material, the Starrett 505P-7 takes the guesswork out of miter and butt joint cuts and offers a quick and accurate way to measure/mark/cut with speed and accuracy. The tool features an easy to read dial and a durable "Made in America" construction that will give you long years of trouble free service and reliability. And don't worry about a learning curve, the tool features a simple to read dual scale that tells you exactly where to set your saw, so you can measure and cut in an instant. If you've ever struggled with a miter or butt joint cut and wished there was an easier way, consider the Starrett 505P-7 Miter Saw Protractor a wish granted.