Case is 40mm with a thickness of 10.7mm, stainless steel, convex sapphire crystal with anti-reflective coating on both sides, screw-down crown, closed caseback, and water resistant to 100m. Dial is brushed silver-plated, inspired by a rare historic Ingenieur SL execution from the 1970s, with rhodium-plated hands and applied markers filled with Super-LumiNova, and the usual lightning bolt in the Ingenieur logo replaced by “50” for the anniversary. Movement is calibre 32111, automatic, 28,800vph, with double-pawl winding, central hacking seconds, date, and a soft-iron inner case protecting the movement from magnetic fields. Power reserve is 120hrs. Limited to 1,150pcs. A 35mm anniversary version is also available. Priced at CHF 13,200.