The REDiTEST B50ST emergency ballast works in conjunction with an AC ballast to convert new or existing fluorescent fixtures into emergency lighting. The emergency ballast consists of a high-temperature nickel-cadmium battery, charger and electronic circuitry in one compact redcase. The B50ST can be used with most 17 - 215 W 2 - 8 foot T8, T9, T10 or T12 fluorescent lamps without integral starters, including U-shaped, HO, VHO, circline and energy-saving, and 4-pin long compacts. One- or two-lamp operation may be selected see Table 1 . It is also compatible with most one-, two-, three- and four-lamp electronic, standard, energy-saving and dimming AC ballasts. If used in an emergency-only fixture, no AC ballast is necessary. The B50ST is suitable for indoor and damp locations and for sealed and gasketed fixtures, including fixtures rated for wet locations. It is not suitable for air handling heated air outlets or wet, or hazardous locations. For information about specific lamp and ballast compatibility, please call the factory.