The Multiface was a hardware peripheral released by Romantic Robot UK Ltd. for several 1980s home computers. The primary function of the device was to dump the computer's memory to external storage, and featured an iconic 'red button' that could be pressed at any time in order to activate it. As most games of the era did not have a save game feature, the Multiface allowed players to save their position. However, this feature also allowed users to create backups or pirate copies of software. Copyright infringement was discouraged, yet possible in earlier models, but was made more difficult in later models by requiring the Multiface to be present when re-loading the dumps into memory.
Multifaces were released for 8-bit and 16-bit microcomputers, such as the ZX Spectrum, Amstrad CPC 464 & Atari ST. Different models had slightly different features.
Source: Wikipedia, "Multiface", available under the CC-BY-SA License.