Device Leveler and Retainer | Retainer,Leveler,Device Leveler | Specification-Grade Emergency Ballast Operates One or Two Lamps (4' or Shorter) or One 8' Lamp. Factory or Field Installed Within Fluorescent Fixture Ballast Channel. Upon Interruption of Normal Power Battery Pack Automatically Strikes and Operates Lamps | Use Through Knockout to Connect Box to Conduit Coupling; Use With a Locknut to Connect Two Boxes Side by Side or Back to Back; Use With a Locknut to Connect Fixture Housings in Continuous Runs; Rigid Conduit Threads (Nps)Furbay Electric Supp