This was the 6-slot bus system. This Gemini item uses a proper PCB, but most of the Nascom users made their own using 78-way Vero card-edge connectors (now sadly obsolete) and Veroboard.
I attempted to fit this into a standard card frame and I can assure you that it’s not worth the hassle! The edge connectors are on a slightly smaller spacing than the standard 1 inch, and don’t appear to be on metric centres either.
This example is attached to a battery holder. I think it may have been intended to keep either a real time clock running or maintain the memory in some CMOS RAM. Either way, I would have preferred an on-board battery.
nascom.info 