View source for EPSA Super-Compressor

==EPSA Super-Compressor==

===What is a “Super-Compressor” dive watch? ===

“Super-Compressor” refers to a patented case sealing method developed by watch case manufacturer Ervin Piquerez S.A. ([[EPSA]]). The design takes advantage of the water pressure the case is exposed to at depth to press the case back against the o-ring seal . More depth equals more water pressure equals greater seal. Dual crown
Super-Compressor watches typically have a depth rating of 600 ft. This same concept was employed by Omega in the Naiad crowns used on Seamaster 300 watches in the ‘60s. Well regarded as being very high quality and watertight, EPSA manufactured the S-C cases in a variety of styles from the late '50s until bankruptcy closed the business in the mid-'70s. The fact that so many survive today is a testament to their quality.

===Are all Super-Compressors dual-crown, internal bezel watches?===
No. Super–Compressor refers to the method of case sealing and nothing else. Dual crown styles are the most commonly seen, but there are single crown cases that have the Super-Compressor designation.
===Are the large case dual-crown models called “Super-Compressor” and the small case models simply called
“Compressor”?===
No. As stated above the term “Super-Compressor” refers only to the case sealing method. Both the small cased
models (36mm) and large cased models (42mm) of the dual crown style are Super-Compressors.

===What are Compressor and Compressor 2 types, and how are they different from the Super-Compressor?===
From Both the Compressor and Compressor 2 types have snap on case backs. Compressor 2 types use a shaped case (i.e. square, cushion or tonneau), not round. Compressor and Compressor 2 watches while water resistant, are commonly seen in "fashion" watch styles, and while designed to be water resistant are not dive watches. The exception to this is the triple-crown Compressor cased JLC Polaris. The Super-Compressors use a screw-on case back, excepting the Enicar models which use a bayonet mount caseback. The Super-Compressor designation is used on both single and dual-crown types.

===Do all Super-Compressors have a screw-on case back?===
Many of them do, but not all. The Super-Compressor cases manufactured for the [[Enicar]] Watch Co. are the exception. They use a bayonet mount for the case back, similar to the way a camera lens mounts.

===Are all dual-crown, internal bezel watches EPSA Super-Compressors?===
 No, similar styles were produced by a number of other manufacturers. Dual-crown internal bezel watches that are very likely EPSA manufactured cases have been seen, but do not employ the S-C technology for the case back. 
Dual-crown replica watches have recently begun to appear on ebay. These watches have a number of Super-Compressor design details like cross-hatched dual-crowns and an internal bezel, but are modern/new manufacturer replicas, not authentic Super-Compressors.

===How do I identify an EPSA dual-crown Super-Compressor?===
 EPSA S-C watches can usually be identified by the trademark dive helmet inside the case back, sometimes on the outside of the caseback. Dual-crown S-C watches typically (but not always)have cross-hatched crowns, sometimes you’ll see the manufacturers signature with the cross-hatching behind. With few exceptions, the crowns are characteristically fat and chunky. If it's a screw on case back there should be a spring assembly inside
the caseback rim. The upper crown located is at 11 minutes and the lower crown at 19 minutes on the case, regardless of the case size or style. EPSA Super-Compressor Brevet (patent) numbers may also be present:
Screw-on case backs carry the numbers 317537 and 337462. Bayonet mount (Enicar cases) case backs have the number 314962.