Starrett 505A-12 12" - 300mm Aluminium Miter Protractor Takes error-prone calculations out of miter cuts Upside down or backwards, the reading is always correct Scale shows angle for a miter joint and single cut Saves time and reduces waste Ideal for carpenters, plumbers and all building trades 12-inch miter saw protractor with two scales--red "miter cut" scale and black "single cut" scale Allows direct transfer of the work angle to the miter saw in 3 steps with no calculations Durable 1/4-inch thick aluminum alloy; Teflon O-ring for smooth, precise operation 7-inch version also 12-inches long; 1-1/2 pounds; 1-year warranty