Two brands built on engineering precision have marked a significant milestone together. IWC Schaffhausen has released a limited-edition 140-piece Big Pilot’s Watch to celebrate the 140th anniversary of Mercedes-Benz, pairing the occasion with the debut of a genuinely novel perpetual calendar mechanism.
The watch, reference IW329603, is limited to exactly 140 pieces, one for each year since Carl Benz filed the patent for the first automobile in 1886.
A New Approach to the Perpetual Calendar
The headline complication here is the Perpetual Calendar ProSet, which IWC introduced earlier in 2026 at Watches and Wonders in Geneva. It represents the brand’s first complete reimagining of the perpetual calendar since watchmaker Kurt Klaus developed the original IWC version in 1985.
The key distinction is how the calendar is set. Traditional perpetual calendars typically require pushers, multiple crown positions, or careful sequencing to correct the date. The ProSet allows adjustment both forward and backward using a single crown position, the same way you would set the time. IWC protects the underlying mechanism with four patents.
The engineering behind that apparent simplicity is considerable. The module relies entirely on gears with complex geometries, manufactured using the LIGA process, a microstructuring technique based on lithography and electroforming. The moon phase display, accurate to within one day every 1,040 years, works correctly for both northern and southern hemisphere viewers via IWC’s Double Moon system.
Case, Dial, and Movement
The watch uses a 42-millimetre brushed and polished stainless steel case. The black dial carries solid gold appliqués and gold-plated hands, with a white-printed minute track for legibility. Four subdials show the date, month, day of the week, and moon phase, while a four-digit year display sits between seven and eight o’clock.
Power comes from IWC’s in-house 82665 calibre, featuring a nickel-phosphorus escapement, a silicon hairspring, and a ceramic-reinforced bidirectional Pellaton automatic winding system. Power reserve stands at 60 hours. The watch ships on a black rubber strap with IWC’s tool-free EasX-CHANGE system for swapping straps.
On the sapphire case back, IWC has engraved the first joint logo used by Daimler Motoren-Gesellschaft and Benz & Cie. following their 1926 merger, combining the laurel wreath from the Benz emblem with DMG’s three-pointed star. It is a neat historical detail that grounds the piece in the anniversary it commemorates.
A Partnership Now in Its Third Decade
IWC and Mercedes-AMG have been partners since 2004. IWC became the official engineering partner of the Mercedes-AMG PETRONAS Formula One Team in 2013, and the two brands have since produced a steady stream of co-branded watches, including Formula One team editions and two Big Pilot models inspired by the G-Class.
This latest release sits at the more technically ambitious end of that catalogue. The Perpetual Calendar ProSet is not a cosmetic collaboration piece, it is a mechanism IWC developed independently and has now chosen to debut in a partnership context. For collectors, that distinction matters.
With only 140 examples available worldwide, demand is likely to outpace supply considerably. Whether the ProSet mechanism eventually appears in wider production will be worth watching.
