I see your delma, they don't give much information on the bulb, and I can't tell much from the pictures either. Though one thing concerns me in particular, it says "SODIUM FLOOD
lights." I think there is a difference between
high pressure sodium, and sodium. I also don't know if the box on the fixture holds a
ballast or not. I also don't see anywhere where it mentions one, and I believe that both
metal halide and high pressure sodium require a ballast. Without knowing exactly what bulb they are using I can't even look it up on the net. You can always contact the seller and ask them specificity what bulb it has (like brand and stock numbers for replacement), and if it uses a ballast. Then it would be possible to look it up.
P.S. I don't know if it matters, but I noticed that the seller "Will arrange for local pickup only."