Whatever that is, its a retail unit, and not a prototype. I assume its a CDROM for a NEC PC, but not a PC Engine. Some NEC computers used CDROMs very similar to the PC Engine CDROM2, but not the same thing.
The PC Engine/Turbografx SCSI adaptor was to be for Duos. The SCSI adaptor fit into the HuCard slot. There was, I think, at least one working bare board prototype. It looked like one of those diving board TG-16/PCEngine HuCard adaptors with a huge ribbon cable comeing out of it.