MLBG42FBU Electronic Fluorescent Ballast Body; 120 – 277 Volt, 42 Watt, 1-Lamp. Ballast body has high temperature silicone o-Rings gaskets, optic gaskets that offers superior sealing. It has high hinge mounting hoods ideal for added safety during installation and servicing. Ballast body includes instant on nature that eliminates the possibility of an extended blackout due to a momentary power dip.