In the event your power goes out, your LED fixtures won't with KT-EMRG-LED-5-500-K1. This Smart Safe LED emergency back-up incorporates Keystone's Constant Wattage technology so that it delivers every-time its needed. It helps to detect the electrical load of the LED fixture and adjusts the output to the appropriate level. The battery pack is separate from the battery and has a metal shroud which allows it to be mounted remotely, so it does not interfere with the design of LED architectural fixtures. It features 5 watt LEDs that deliver 500 lumens of light a minimum of 90 minutes. It also features a 2-in-1 LED test switch and indicator light that helps provide instant reassurance the system is working properly.