What should not be done when handling the NVG unit?

Using mixed battery types should not be done when handling the night vision goggle (NVG) unit because it can lead to inconsistent power delivery and potential damage to the device. Different battery types can have varying voltages, chemistries, and discharge rates, which can create imbalances in the electrical system of the NVG. This can result in reduced performance, failure to function, or even permanent damage that compromises the night vision capabilities.

Proper maintenance of the NVG involves ensuring that the power source is reliable and suited specifically for the unit. The other options—inspecting the goggles frequently, cleaning contact points properly, and storing the unit in a protective case—are all considered best practices for maintaining and preserving the integrity of night vision goggles. Regular inspection ensures that any issues are caught early, proper cleaning maintains the quality of the lenses and electronic contacts, and storing the unit in a protective case safeguards it from physical damage when not in use.