Micronauts is the American version of a toy line from Japan called Microman. They were imported into the USA, in the mid 1970's, by a company called Mego Corporation, and the line consisted of action figures, robots, vehicles, play sets, etc. They came with names like Ultronic Scooter, Warp Racer, Time Traveler, Photon Sled, Hydro Copter, Space Glider, Sharkos, King Atlas, and Red Falcon.
By 1980, it was over, but the rights to Micronauts were purchased by Palisades Toys in the early 2000's, and a re-released was soon put to store shelves. Last we heard, the Micronauts were not dead, and Hasbro had plans to re-launch the brand at some point.