The text under the photo says (Google translate) that it's a 2 Amp output power pack:
"So with that 2A high current,
HO HO gauge is also compatible with long-span interior light so easy to organize. "
So it sounds like it's a high-output pack compatible with lighted HO trains (which could draw more than the standard Kato pack if they use bulbs and are fairly long).
I was about to mention that there were more photos
on this site, but to2leo beat me to it.
Despite it being labeled "Super D", both sites use the English label "Hyper-D" in their text: パワーパック「HYPER-D」 (power pack "Hyper-D")