Multiface ST
The Multiface ST was a multifunctional cartridge made for the Atari ST by Romantic Robot.
Features
The Multiface ST plugs into the Atari ST's cartridge port as well providing a pass-through connector for the Atari monitor port. The Multiface ST claims to be able to copy any program but to prevent piracy you need to have the Multiface ST plugged in to run the copy.