Acorn Electron Plus 1

The Acorn Electron Plus 1 was a basic Acorn Electron but with an expansion unit providing two ROM slots, an analogue interface and a parallel port. The analogue interface was normally used for joysticks, the parallel for a printer.

As you can see from the image above, the Plus1 unit bolted on to the back of the Electron making it similar in size to the BBC Model B