Movement family
LeCoultre's 2.45 mm automatic of 1967 — calibre 920, and 921 with date — made for Audemars Piguet, Vacheron Constantin and Patek Philippe, which each gave it their own number.
2 directions from here
3 curated films, each naming the calibre or a member of its family in its title
Names “2120” — Audemars Piguet's number for the 920
Names “k2121” — AP calibre 2121, the dated version (LeCoultre 921), used in the first Royal Oak — part of this family
Names “2121” — AP calibre 2121, the dated version (LeCoultre 921), used in the first Royal Oak — part of this family
