The end of the JLC 920 era
For fifty years, from 1972 to 2022, every Royal Oak Jumbo ran the Cal. 2121, an Audemars Piguet-finished version of the Jaeger-LeCoultre Cal. 920 ultra-thin automatic. With the 50th Anniversary of the Royal Oak in 2022, AP retired the 2121 and introduced the Cal. 7121: a fully in-house design with no JLC base, no third-party dependency, and modern specifications.
Designed for the same case
The 7121 was engineered to slot directly into the existing Royal Oak Jumbo case dimensions. Critically it preserves the 3.2 mm thickness that the 2121 made possible, allowing AP to keep the new ref. 16202 at the same 39 mm × 8.1 mm Jumbo proportions that have defined the watch since the 1972 ref. 5402. The off-centre rotor is in roughly the same position; the dial layout, with the date at 3 and three hands, is unchanged from the buyer's perspective. What you cannot see is the new architecture below.
What is new
The 7121 brings several modern features that the 2121 lacked:
- 55-hour power reserve (up from 40 h)
- Free-sprung balance with variable inertia (replacing the regulator arm)
- Ball-bearing-mounted rotor (more efficient, longer service life)
- 32 jewels (vs 36 on the 2121, but the gear train is simplified)
- Improved shock protection on the balance staff
- All components manufactured by AP's own movement department in Le Brassus
Watches using the 7121
At launch, the 7121 went into the ref. 16202ST "Jumbo 50th Anniversary" steel (limited dial colours and metals through 2022-2023), the ref. 16202OR in pink gold, and the 16202BC in white gold and platinum versions. The "50th Anniversary" oscillating weight inscription appeared on initial-year production; later 2023+ examples carry the standard rotor. As of 2025 the 7121 has expanded into other Royal Oak Extra-Thin variants and is the platform for the next generation of slim Royal Oak watches.
Where it sits
For Audemars Piguet the 7121 is a strategic milestone: ending the half-century JLC base era and proving the brand can build an ultra-thin in-house automatic to its own design. For collectors, it raises a question still being debated: does the 16202 with the modern 7121 supersede the 15202 with the historic 2121, or do the two co-exist as different chapters? Auction prices through 2024 suggest the 15202 retains a premium for its "last of the JLC-base" historical position; the 16202 is the technically superior watch but the 15202 is the closing of a fifty-year era.
