What types of clones exist?
Probably the most famous is the Gemini, an inexpensive clone 2600 made by Coleco. It sports an all black, box-shaped enclosure with six small slide switches (say that fast) on top of front panel. On the back panel, there is an RF modulator port and a power adapter port. Two joystick ports and difficult switches live on the front panel. Bundled bits include two dual-joystick/paddle controllers, a 9volt/500ma DC adapter, an RF cable, a TV switch and Donkey Kong and Mouse Trap carts. Sample wording: Coleco Gemini VGS – Coleco Ind., Inc., Serial # AG0145189.