* [[Dk'tronics memory expansion]]
* [[Dk'tronics Silicon Disc]]
* [[Dobbertin EPROM 224]]([[Dobbertin]])* [[Dobbertin Memory Expansion]]([[Dobbertin]])* [[Dobbertin]] [[Universeller EPROM Programmer 4004]]([[Dobbertin]])
* [[Inicron RAM-Box]] (Inicron)
* [[RAM BOX]] 512Kb memory expansion