IP20 Lithium Ion Battery Emergency Light Recessed Blade With Spitfire Lamp White 4W EGS4RS

What is the purpose of emergency lighting?
 
The purpose of emergency lighting is to provide a level of illumination in exit pathways that will enable the occupants of the building to exit safely in the event of a main power failure.
Emergency lights are essential in buildings, offices, and public spaces as they provide illumination during power outages and emergencies.
What is the difference between maintenance and non-maintenance emergency lights?
 
Emergency lights (e.g. LED tubes with spare batteries) will provide normal lighting levels when mains power is available; When the main power fails, the emergency lights will rely on battery power at lower lighting levels. Usually used in parking lots and fireplaces.
Non-maintenance accessories (e.g. spitfire emergency lights) do not light unless the main power supply fails. Usually used in business offices.