Audemars Piguet
AP cal 2121
Swiss lever · introduced 1972
Beat rate
19,800 vph
Power reserve
40h
Jewels
36
Introduced
1972
Escapement
Swiss lever
The cal 2121 is among the thinnest automatic movements in production at 3.05 mm, derived from the JLC cal 920 in 1967 and finished to haute horlogerie standards by AP. Its slim architecture defines the Royal Oak Jumbo's 6.3 mm total case height. The slow 19,800 vph beat rate and single barrel limit the power reserve to 40 hours, a deliberate trade-off for the ultra-thin profile. AP has produced it continuously for over fifty years.
Specifications
Beats per hour
19,800
Jewels
36
Power reserve
40h
Diameter
28.0mm
Height
3.05mm
Escapement
Swiss lever
Introduced
1972
Finishing
Haute horlogerie
Service interval
5 years
Service cost tier
Haute
Complications
date
Known service issues
- Power reserve of 40 hours requires daily wear or a winder; thin movement architecture leaves limited room for a second barrel
- Haute horlogerie service costs are significant; expect 2,000 plus at an authorized service center
Notable in
- AP Royal Oak Jumbo 15202ST
- AP Royal Oak Extra-Thin 15500ST
- AP Royal Oak 50th Anniversary 16202ST
References in our catalog using this caliber
Buying advice
Practical guides for buying a watch with this caliber on the pre-owned market: