Displays absolute and relative angle measurements in a large, easy-to-read LCD window 6" (150mm) Stainless Steel Protractor Arm with knurled locking nut Perfect for installing crown moldings, cabinetry, counters, staircases, roofs, windows or flooring One-button zero calibration ensures accurate readings every time Calculate angles by swinging open the 6" stainless steel pivoting arm, which can be locked in any position Display offers a "holdin function and is easily inverted, or flipped, 180 degree(s)s for reading upside down Accuracy: 0.1° ; Resolution: 0.05° ; Range: 0.00º to 180.00º Battery included; replacement battery CR2032 1.55V