Linear Fluorescent Ballasts
Match the replacement ballast to four things on the old label: lamp type (T8, T5 or T12), number of lamps, input voltage (120V, 277V or universal 120-277V) and starting method. Instant start is the most efficient for lights left on; programmed start extends lamp life where occupancy sensors switch lights often. Wire it to the diagram on the new ballast, not the old one. If you are replacing ballasts one at a time, an LED Type B tube may be cheaper.
Guide: How to find the right fluorescent ballast (and when to skip it)
