Athena Power or Athenatech?
Athenatech are cheaper units like Okia, Deer or Powmax. It was probably pulled from an Athenatech case. I wouldn't give someone $1 for one.
Athena Power is the in house brand of A+GPB. Better quality. About the level of FSP's Saga series or a Topower. But you can get a new one for $80, so $50 isn't much of a deal.