Ruler and Protractor Set: Measures lengths and angles with an accuracy of 0.3. This protractor is ideal for DIY projects, woodworking, decorating, and machining. 360-degree measurement: The protractor's hinged mechanism allows you to measure internal and reverse internal angles from 0 to 360 degrees. Large LCD display: The large, full-screen LCD display is easy to operate with only three buttons, making measurement and reading easier. Power supply: The CR2032 3V lithium battery has a high-capacity sleep function and an automatic shutdown function, providing more than 2,000 hours of continuous operation, saving energy and extending battery life. Lightweight and durable: The thickened and widened ruler is made of ultra-strong nylon and fiberglass for excellent rigidity, wear resistance, and deformation resistance. LCD display Lock function The large, full-screen LCD display is easy to use with just three buttons, making measuring and reading easy.