1960s Benrus Ultra-Deep (Ref. 6089) Super-Compressor

Patented in 1956 by Ervin Piquerez SA (EPSA), the SuperCompressor case possessed a unique sealing system that set it apart from other dive watch cases of the day. When exposed to higher water pressure, the spring-loaded case back of the SuperCompressor case sealed even tighter. Another innovation with the SuperCompressor was its a three-pronged approach to securing the bezel. Whereas the bezels of most dive watches of the period rotated in both directions--running the risk of the diver miscalculating the amount of air left in his tank--the bezel of the SuperCompressor included an internal timing ring, only rotated in one direction, and locked.  The diver must rotate the bezel with an additional crown, giving the SuperCompressor case its distinctive twin crown appearance. While not the best innovation in practice (due to the difficulty of manipulating a crown with diving gloves), the SuperCompressor case gained popularity. Dozens of other brands released dive watches with SuperCompressor cases, the most notable being Jaeger-LeCoultre, Enicar, Universal Genève, and IWC, Benrus, and Longines.