Audemars Piguet 2120

The Caliber 2120 is one of the most famous movements in the watch industry, originally created by Jaeger-LeCoultre and also used by Vacheron Constantin and Patek Philippe. At only 2.45mm thick, it remains one of the slimmest automatic movements ever made. It features a suspended barrel and a 21-carat gold oscillating weight on ruby rollers (no ball bearings). Manual finishing includes polished bevels, satin-brushed edges, and perlage on the recesses. This legendary movement powered the original Royal Oak 'Jumbo' ref. 5402ST from 1972 and was discontinued in 2022 after 55 years of production.