Starrett Plastic Mitre Protractor 180mm 505P-7The 180mm Plastic Miter Protractor takes error prone calculations out of the process of miter cuts. Tool is ideal for carpenters, plumbers and all building trades that require the measuring and transferring of angles and invaluable for home use Features: Easy to use tool has two laser engraved 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