IWC GST Perpetual Calendar Stainless Steel IW3756-15

The 3756 runs on the self-winding calibre 79261, which combines a chronograph with a secular perpetual calendar, a moon phase at 12 and a four-digit year display good until 2499. The case has a screw-down crown and case back and a sapphire crystal.

The case is 43 mm wide and 16 mm thick; the titanium English version is the IW3756-03. In steel, the English black dial sits beside grey (IW3756-07), salmon (IW3756-11), white (IW3756-19) and silver (IW3756-23) versions, while the IW3756-13, IW3756-14 and IW3756-16 are the same black-dial steel watch in German, Italian and French. Unlike the GST Aquatimer (IW3536), it has no rotating dive bezel.