2 stainless steel rules with 7 inch and 4 inch blades with photo etched graduations inch and metric; display reads continuously as arms are adjusted hold function so you never forget a measurement *takes both inside and outside angle measurements *large clear LCD display strong blade lock holds securely for transfer of measurements *reversible reading that allows you to Flip the display reading to right side up measures range: 0-360 Degrees *powers off after 5 minutes of nonuse resolution: 0.05 degree (that's 5/100th of a degree!) repeatability: 0.1 degree battery: 3V CR2032 with life of approximately 1 year and comes with an extra battery.