37.5mm Planet Ocean, Ladies Constellation, 34mm Aqua Terra (add yours in the comments below…)
The Omega caliber 8520 is an in-house automatic movement found in smaller ladies and mid-size Omega watches.
In Omega’s own words:
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. Rhodium plated finish with exclusive Geneva waves in arabesque.