Ruler and protractor combination: measure length and angle with an accuracy of ±0.3°. This protractor is a good choice for DIY projects, woodworking, decoration, machining. 360 Degree Measurement: The hinge mechanism of the angle ruler allows a full range of 0 to 360 degrees to measure interior and reverse interior angles. Large LCD Display: Large full-screen LCD display, easy operation with only three push buttons, easy to measure and read. Power Supply: CR2032 3V lithium battery (not included), large standby capacity with automatic power-off function, can work more than 2,000 hours, saving energy consumption and extending battery life. Lightweight and Durable: Thickened and widened ruler with ultra-strong nylon fiberglass engineering material, good rigidity, wear resistance, no deformation. Features: Material: Fiberglass nylon Length: 0-300mm Measuring range: 0-360 ° Resolution: 0.05 ° / 3; Accuracy: ± 0.3 ° Working power: 3V Battery model: CR2032 (not included) Operating time: 5000