The Jafa Shadow RAM Board is a small unit which fits inside the Acorn Electron and provides two extra 'modes', accessed by a small switch drilled into the left side of casing. The three modes are therefore: Normal (where the MRB is not detected), Turbo (where the MRB is used to share the workload of the CPU and games run at a much faster speed) and Shadow (where the memory usually used for the screen can instead be used as workspace).

The Jafa Shadow RAM Board is practically identical to the Slogger Master RAM Board.

The Jafa Shadow RAM Board came supplied with a User Guide and was originally available by mail order only from Jafa Systems for £89.99.