This obscure GST Chronograph Perpetual Calendar was produced for a very limited period between 2001 and 2004. The watch offers an array of complications inside a decidedly rugged and sporty 43mm steel case and is paired with a steel bracelet. Displayed on the salmon dial in four sub-registers are a perpetual calendar, moon phase and a 12-hour chronograph. The movement powering this rarely-seen reference is IWC’s calibre 79261, which is a highly modified Valjoux 7750 with the addition of renowned watchmaker Kurt Klaus’s perpetual calendar system.