Gérald Genta designed the original Ingenieur SL in 1976, the same decade he created the Audemars Piguet Royal Oak and Patek Philippe Nautilus, two watches that reshaped what a luxury sports watch could look like. IWC’s 50th-anniversary tribute comes in two sizes, both limited to 1,150 pieces, and both replace the current Ingenieur’s grid-textured dial with a rarer vertically brushed silver finish pulled from a 1970s variant of the original SL. The traditional lightning-bolt logo beneath “Ingenieur” is swapped for a discreet “50” as the only overt nod to the anniversary. The 40mm version runs IWC’s in-house Caliber 32111 with a 120-hour power reserve and a soft-iron inner case for magnetic protection, while the 35mm uses Caliber 47110 and a sapphire display back instead. Both keep the Ingenieur’s signature five-screw bezel and fully integrated, satin-finished bracelet.