Electronic Protractor Features Include.. Embedded 25 lb. pull magnets Full, 360° measuring range Accuracy: ±.2° Repeatability: ±.05° Resolution: .05° Invertible display feature Voltage: Standard 3V lithium battery The Digi-Pro electronic protractor includes embedded magnets for unique measurement areas. On/Off, Zero, Hold and Reverse feature to invert the display for easier reading in certain situations.