8521 sans date.
Self-winding movement with Co-Axial Escapement for greater precision, stability and durability. Free sprung-balance system with silicon balance-spring. Automatic winding in both directions to reduce winding time. Oscillating mass and balance bridge in 18 Ct red gold. Luxury finish with exclusive Geneva waves in arabesque.
All watches using this caliber:
18.104.22.168.55.003 Omega Seamaster Aqua Terra 150M Co-Axial 30 White Gold / Diamond / MOP / Bracelet
22.214.171.124.99.003 Omega Seamaster Aqua Terra 150M Co-Axial 30 White Gold / Baguette / Baguette / Bracelet