Field Installable LED Emergency Lighting System by Keystone – Emergency LED Systems. The Emergency LED kits give safe and efficient lighting during an emergency. The Emergency LED retrofit kit includes: one linear-shaped LED module, emergency LED driver, NiCad babattery pack, required mounting hardware, and a UL Classified label to attach to the fixture after installation. This emergency lighting kit can be used with T8 LED troffers that have been retrofitted. They can also be used in fluorescent fixtures in lieu of a fluorescent emergency ballast.