Micro-rotor movements are aesthetically much more pleasing and Buren was the first company to introduce them, they succeeded in making a very thin, very accurate automatic movement by employing revolutionary mechanisms that functioned reasonably well in a variety of different levels of execution and elaboration. As a classy example of a turning point in the history of both Hamilton and automatic movements in general, a Buren powered Thin-O-Matic makes for an interesting, horologically significant addition to any watch collection."
The first ever micro-rotor automatic watch movement was patented by Uhrenfabrik Büren A.G. in the mid 50s. When their "planetary rotor" automatic movement was released in 1957 in the "Super Slender" line, it was one of the flattest automatics of its time and derivatives of the movement competed with the Universal Geneva micro-rotor for thinnest automatic in the world for many years. The most famous implementation of the Buren micro-rotor was to be found in Hamilton's "Thin-O-Matic" line. "