Technical Inspection
It is recommended to carry out a technical inspection before each use of the 
device. Check the following:
External view (there should be no cracks on the housing).
The state of the objective, eyepiece and rangefinder lenses (there 
should be no cracks, spot, dust, deposits etc.).
The state of the rechargeable battery (should be charged) and the 
electric contacts (should be no signs of salts, oxidation or debris).
Correct functioning of the controls.