Ruler & Protractor Combination - Measure both length and angle with accuracy of 0.3, can be used for woodworking,construction,sketching, drawing, Crown molding, baseboard molding and more. Measure 360 Degree - Allows a full range of 0 to 360-degrees to measure inside outside and reverse angles. Measuring length: 0-200mm. LCD Display - Simply operate with only three press-buttons, easy to measure and easy to read. Display has a hold function to lock movement for accuracy. Light & Durable - With super-strength nylon glass fiber engineering material, good rigidity, wear resistance, no deformation. Power Supply - CR2032 3V lithium battery power supply, 5 minutes automatic power-off function, can work more than 2000 hours.