Super Compressor diving watches are a category worthy of study to any vintage sports watch enthusiast. 

The name refers their case design; a "compressor" system was designed to become more watertight the deeper the watch went under water.  The secret was a gasket system in the case back that was compressed as the water pressure increased.  Although compressor cases proved to be more complicated to make and no more effective than well-designed screw backs, this style of diving watch was very popular in the 1960s, and were utilized by a number of brands, including Jaeger-LeCoultre, Longines, Enicar, Droz, Blancpain, Universal Geneve, and Zenith, to name a few.  All of these watches had their cases provided by EPSA (Ervin Piquerez, S.A.) the leading manufacturer of compressor cases at the time. 

The example we are presenting here is branded by Hamilton, and features a 36mm EPSA case with dual crowns.  The upper crown is used to operate an internally rotating bezel ring, used for timing dives.  Unlike watches with external bezels (think Rolex Submariner), this design was intended to be less prone to accidental rotation, making it a safer choice for divers.  This timepiece is in extraordinary original condition and features an automatic movement with date function.  It is perfectly sized for daily wear, and looks every bit the part of a true vintage diving watch.  These are getting to be scarce finds in good original condition!

For more information on the history of compressor-cased diving watches, click over to Scubawatch.org, .