Sinclair Spectrum Plus
The ZX Spectrum Plus was essentially a 48k Spectrum in a new case with an improved keyboard, though opinion generally differs about how good the keyboard was. The case also had a reset button on the left hand side, which meant you did not have to unplug the power supply in order to reset it like the earlier machines. They cases were also sold as an upgrade to existing owners of 48k machines. By no stretch of the imagination was the Spectrum Plus; a new model.