Marie,
It is a "special" plug, not your normal 3-prong plug you find on most ballasts. The canopy has 3 - 175w MH and 2- 6' long vho's.
All wiring comes into the ballast on one multi-pin plug. So it is pretty much a package deal, can not seperate the ballast from the canopy. I never used the VHO's, just the 3 - MH's.
Chuck