Introduced in 1992 the ref. 5040 was Patek's first-ever tonneau-shaped QP link and it link even came outfitted with Breguet numerals and Breguet hands making it the first serial-production Patek Philippe wristwatch to include the combination. The ref. 5040 features the self-winding caliber 240Q with micro-rotor the same perpetual calendar with link moonphase movement found in the better-known and more classically styled ref. 3940.