The Magnavox Odyssey was the very first home video game system. Created by Ralph Baer ("The Father of home video games"). The system was released in May 1972 and reportedly sold over 100,000 units that year.
The Odyssey is made of transistors, resistors, and capacitors. There are no real hardware "specs". Odyssey used cards that contained pin outs to change game settings. Plastic overlays that could be placed over the TV screen created graphics and color, but the actual display consisted of white squares (Paddle and ball) on an all black background.
This version was sold only in Magnavox stores.