AtlantaLightBulbs.com stocks many of the commonly used emergency back up ballast. We carry brands like Fulham, Beghelli, Philips Bodine & Iota. To find your ballast look up the lumen output you are trying to provide when the back up ballast is turned on, then match up the type of lamps the ballast is operating. Many have the equivalent manufacturers listed in the description. If you cannot locate the one you need please click on the live chat icon or call us, we are here to help!