PB: The movement alone was 38 millimetres in diameter, so it obviously needed an unusually large case. That’s how we came to resurrect the Big Pilot’s Watch Calibre 52 T.S.C. from the 1940s. At 55 millimetres in diameter, this highly functional observer’s watch was still the largest wristwatch IWC has ever built. It supplied the technical specifications for the Big Pilot’s Watch and was the inspiration for the size, dial, and distinctive, oversized crown.