The VEM5000DV-L emergency ballast from Espen Technology is designed to operate with fluorescent T8 lamps as well as Espen's Retroflex and Retroflex HE lines of plug-and-play LED T8 tubes. It works in conjunction with the AC ballast to allow the same fixture to be used for both normal and emergency operation. When AC power fails, the ballast switches to emergency mode and keeps one lamp illuminated at a reduced lumen output for 90 minutes maximum. It is suitable for use in new fixtures or retrofit applications.