Function:
1. Measuring range:50/70/100 meters
2. Single measurement, continuous measurement (maximum/minimum value)
3. Front benchmark, back benchmark
4. Addition measurement, subtraction measurement
5. Area, volume,Pythagorean theorem measurement
6. Timing measurement
7. Data storage
8. Unit: meters, feet, inches
9. 520nm green light
10.Built-in lithium battery

 Sketch map: