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 0-360 degree range for measuring inside and reverse inside 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, large sleep capacity with automatic power off function, can work more than 2000 hours, saving power 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 LCD display Hold function Large full-screen LCD display, easy operation with only three push buttons, easy to measure and easy to read. Battery model: CR2032 Power supply: 3V Working time: 5000 hours. Automatic screen closing time: 6 minutes.