The Starrett 505A-7 7-inch ProSite Protractor takes error-prone calculations out of the process of miter cuts. Simply set your saw to the angle that you read. Upside down or backwards, the reading is always correct. This easy-to-use tool has two scales. Miter cut scale transfers readings directly to the miter saw for miter joints. Single cut scale transfers readings directly to the miter saw for butt joints. Features: Teflon O ring for smooth and precise operation Made from durable 1/4-inch aluminum Laser engraved for accuracy What's In The Box: Starrett 505A-7 7-inch ProSite Protractor