These models represent 2 holders for the adapter board that is installed into Yamaha MSX2/MSX2+ YIS805 or similar computers to relocate the Z80 socket to a more accessible place. The holders are glued to the motherboard with the help of 2-sided sticky tape. The board is set on those holders and secured with the help of 2 small screws.
I am providing the source of the model for anyone to adjust the holders if necessary.
The adapter board's files can be found in the RBSC's repository:
The holders should be printed with their flat surfaces placed on the printing bed.