Low-Profile Surface Mount Emergency LED Lighting. Automatic Light upon failure of normal utility power. Internal solid state transfer switch automatically connects 4.8V nickel cadmium battery and provides minimum of 90 minutes of emergency lighting. Integral charger auto-initiates to recharge a discharged battery within 24hrs. Self-Diagnostic Test feature diagnoses the unit to ensure reliable performance and operation. Die Cast Aluminum enclosure with Photocell Sensor and UV Stabilized Polycarbonate lens for 94% light transmission. Quick Mount via back plate or top conduit knockouts. Built to Comply with US and Canadian Safety Standards. Meets UL924, NFPA 101 Life Safety Code, NEC, OSHA, and most Local & State Codes.