Mesee Combination of 2 in 1 Digital Angle Finder Protractor Ruler.<br> - Ruler and protractor combination for easy measuring length and angles. Both metric and imperial sizes laser-etched on the edge of the ruler.<br> - LCD Display, calculating angles quickly and accurately, digital display clearly, convenient to measure and easy to read even in the darkness.<br> - 360-degree Reversal Design, allows a full range of 0 to 360-degrees to measure inside outside and reverse angles.<br> - Locking Knob Design, convenient to lock the angle at any position, the hold button can hold the angles at any time.<br> - Perfect measurement tool for DIY family projects, construction projects, woodworking projects in measuring, sketching, drawing, etc.<br> Specification:<br> Material: Carbon Fiber + ABS.<br> Automatically Closed Screen Time: 5 min.<br> How to install in battery?<br> 1. Push in the protrusion at the bottom of the LCD.<br> 2. Pull out the battery box.<br> 3. The negative pole of the battery is facing up and the positive pole is facing down.<br> 4. Push the battery box back. It's recommended to take out the battery if you don't use it for a long time.<br> Operation:<br> - HOLD Button:<br> "H" will appear on the upper left corner when press, the angle data will be held. To return to measure mode, pls press the HOLD button again.<br> - ON/OFF/ZERO Button:Press this button to re-zero at any angle. Press a long time for power off.<br> - D/M Button:Conversion between Degree and Minute.<br> Package Included:1 X Digital Angle Ruler.