The Commodore VIC-20 was the most successful computer made by Commodore prior to the release of the Commodore 64.
The Commodore VIC-20 was the first Commodore Computer to use the Breadbin case. It had 5KB of RAM, however only just over 3 KB was available for use as the rest was taken up by the BASIC. It had a MOS Technology 6502 CPU and ran on Commodore BASIC version 2.0.
Unlike the Commodore 64, the VIC-20 didn't have any major variants released. Commodore did however make some slight tweaks to the keyboard and the font.