Bottom of the line Asian AGM's like Universal battery. Powertron is just another rebranding label.
These AGMS do not have the super low self discharge, the high charge rat acceptance, or the practically abnormally high CCA ratings of quality AGMS.
They are also likely quite old and compromised capacity wise before they ever leave the shelf.
All used batteries are a crapshoot. Might be worth only the core charge, it might have been well cared for and has a significant portion of its capacity remaining.
At least with flooded batteries one can take a electrolyte sample and perhaps see if it is all cloudy, but an AGM one needs other methods/tools to guess at its condition