Original machines in beige cases and has a membrane keyboard.
The Atari 400 and 800 were the first home computers to use custom coprocessors and the first to use 'sprites' and special video interruptions like display lists, features that will be implemented several years after on the Commodore Amiga. It offered high graphic resolution, lots of colors and great sound capabilities, more than other computers could do then! The
two models had same characteristics, the 400 is the low-cost version, it has only 16 KB (instead of 48 KB), one cartridge port (two for the 800) and a membrane keyboard (a typewriter style keyboard one for the 800).