The Chamaleon 64 is like a cartrige for C64, and can be connected to a real C64, with this, the C64 has more memory, speed, turbo loader, and you can use SD cards for storage. But you can use it in stand alone mode too, and connected to the dock station.
You can see it connected here :
http://www.vesalia.de/e_chameleondock[7760].htm
In stand alone mode, we have C64 core, Minimig core (Amiga 500) and now a Spectrum 48 core
