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The last major revision to the Aquatimer family was in 2014, which involved another update to both the aesthetics and the technical features of the Aquatimer.
The latter two had cushion-shaped cases, also in stainless steel, and were pressure resistant to up to 30 bar/300 meters, with mineral crystals and colored dials; all used the famous IWC caliber 8541, with an automatic winding system designed by IWC's renowned technical director, Albert Pellaton.
It's also a chronograph, with the hour and minute totalizers combined in a subdial at .
The perpetual calendar is not generally thought of as a complication particularly suitable for a sports watch, however the digital configuration used by IWC certainly lends itself better to such an application than any traditional perpetual calendar design.
Thought the GST was discontinued in 2004, that was also the year that a new version of the Aquatimer was introduced.
This version, like the original Aquatimer, had two crowns, with one operating an inner rotating bezel; that design was retained until 2009, when the two-crown design was replaced by a more modern version with a conventional unidirectional rotating bezel.