SuperPower ROM Box
The SuperPower ROM Box from Micro Power Ltd. is a 7-socket Rom Box, there is also a 8-socket version (see advert from May 1986). Also called Micro Power ROM Box.
The box (all boxes, or only that on the photo?) contains Programmer's Toolbox and Basic Extensions ROM.
Not much is known about this interface please add..
Up to 16 of this boxes can be added to the CPC. It's ground ROM-IDs can be selected in blocks of 16: &00, &01, ... &7F. So with 16 boxes and all eight sockets occupied this will add 2 MB or ROM capacity to the CPC.