Finding the right ballast can be difficult. In my particular case I had a ballast failure in a T5 54w 8 lamp fixture. Unfortunately when I received this ballast I noticed that it uses a different connection scheme than the one it replaced - it requires two segments of two lamps each instead of one segment of 4 lamps. I was able to disassemble the high span bracket, cut off the connected ends of the lamps and run additional wires for placement. It would be helpful to have more information in the