Multi-function Digital Protractor: Practical combination: Measuring angle: 0~270°, Measuring accuracy: ±0.3°; Length Measuring range: 7inch/18cm. With horizontal and vertical Spirit level: It can also be used as a spirit level, to help you check and calibrate (NOTE: it will not give a value on the LCD screen, just only help you "Judge"). Data hold function: By pressing the HOLD button to hold the angle values in any time, Operate conveniently. Help users to record the angle values effectively. Mechanical lock: The lock button is just for loosening and tightening according to the user's habit. It can't hold the angle cabinet completely! (If you want to use the data hold function, you need to press the red HOLD button instead of rotating the lock button). Backlit LCD Display: Come with LED backlight display which can read the data clearly even under low light circumstance