This Sandoz is one of the rare vintage Super Compressor divers to offer a 40mm case, in addition to a stunning grey dial. The casemaker Ervin Piquerez S.A. offered its revolutionary Super Compressor cases to many watch brands, including Longines, Universal Genève, and, as seen here, Sandoz. The case relies on the increasing pressure of the water during a dive to further seal the case (with the caseback fitting tighter to the case), which allowed this Sandoz to boast a 200m water resistance. Even more impressive, the two crowns are not even screwed; usually, they bear the characteristic cross-hatched symbol of most Super Compressor cases while a few brands like Sandoz and Bulova chose to have their logo engraved there instead. This diver did not forget that timing was crucial underwater, and integrated an inner rotating bezel to make sure the air supply did not run out before re-surfacing. Whether you're into diving or not, this is a very cool vintage dive watch. Maker: Sandoz Model: Super Compressor Reference: 1704Z-99-22 Year: 1960s Case No: N/A Material: Stainless steel Dimensions: 40mm diameter; 13mm thickness Crystal: Plexiglass Lume: Tritium Caliber: Automatic caliber AS1713 Bracelet/Strap: Green Leather strap Lug Width: 20mm Box/Papers: N/A The 40mm case is in great condition, although the faint engravings on the caseback have become difficult to read. The grey dial does not show any significant imperfections, except for some missing lume plots near the indexes. The superior crown is correctly signed with the Sandoz logo, but the lower crown is likely a later replacement, as it is cross-hatched and not signed. This is a great dive watch that looks even better on the wrist. Comes with a generic watch strap