STAINLESS STEEL ARM: 6-inch (150mm) adjustable stainless steel protractor arm locks into desired position with knurled thumb nut. LOCKS IN PLACE: Thumb screw will lock arm in any position. MEASUREMENTS: Makes absolute and relative measurements along with hold function to freeze measurements.. EASY TO READ: Large display flips when inverted for easy reading. RANGE: Angles in any plane can be measured with accuracy to 0.1 degree and 0.05 degree resolution anywhere within a 0.00 to 180 degree range. GENERAL TOOLS: We're a recognized leader in designing and developing specialized precision tools dedicated to delivering exceptional customer service. We encourage artisans and DIYers to work smarter, measure better, and repair more productively.