Multi-function goniometer: The protractor has metric (mm) and imperial (inch) measurements, and has precise digital readouts, which can measure angle and length. The horizontal and vertical spirit level helps you to check and calibrate (please note: it will not show on the LED, it will only help you to determine). [High Accuracy]: The digital goniometer can measure the internal angle, the external angle and the contra-angle over the entire range from 0 to 360. The measurement accuracy is 0.5 and the resolution is 0.05. You can switch between degrees and minutes to improve measurement accuracy and meet your different accuracy requirements. [Data Hold]: Press the hold button at any time. angle to hold the measurement to help users record the angle value effectively. Locking angle feature helps maintain desired accuracy and is suitable for carpentry, construction or drafting. [Long-lasting battery]: Super endurance, can work continuously for more than 2000 hours. The digital goniometer automatically shuts off to save power consumption and extend battery life. The protractor is equipped with a large LED light for easy reading. [Wide scope of application]: This angle measuring instrument is often used in carpentry furniture, architectural decoration, schools, home DIY, mechanical processing and other areas (including saw blade angle adjustment) Delivery quantity: 1 * angle ruler