For the curious, here is the manufacturer's page. ¥72,000 or $458USD.
It says it can be used with almost all arms (taking that headshell), which probably implies that the overall length of the headshell is the same as usual, otherwise it might mean re-mounting the tonearm a little further away from the spindle to cope with the change in effective length. So this little amp is really small, and miniaturisation and op-amps are not always a good thing if sound quality is more important than convenience/price. I'll be interested to hear what you make of it.