Omega Speedmaster | Day-Date | Triple Calendar "Mark 40" | Ref 3520.50 | Card

The Omega Speedmaster Ref. 3520.50—often called the “Mark 40”—is one of the most complete and practical Speedmasters you can wear. It keeps the classic Speedmaster look but adds a full triple calendar (day, date, and month) along with a chronograph, giving you far more functionality than a standard model. All of this is packed into a comfortable 39mm case, which many consider the ideal everyday size.

The dial is where this watch really stands out. It’s detailed, but laid out in a way that still feels balanced and easy to read—something Omega executed extremely well on this reference. The mix of complications gives it a more technical, interesting feel compared to traditional Speedmasters, while still staying true to the overall design.

Powered by the Omega Calibre 1151 automatic movement, it offers reliable performance with the convenience of self-winding. What makes the 3520.50 special is how well-rounded it is—you get the look of a Speedmaster, the usefulness of a calendar, and a size that works every day. It’s a watch that does more, without feeling complicated to wear.

Condition

Please review the photos carefully for an accurate representation. Light scratches or signs of wear consistent with age and normal use may be present and do not affect functionality.

Technical Data

• Reference: 3520.50

• Case Diameter: 39mm

• Case Material: Stainless steel

• Bezel: Stainless steel tachymeter bezel

• Dial: Black multi-function dial

• Crystal: Sapphire crystal

• Water Resistance: ~30 meters

• Bracelet: Stainless steel bracelet

• Movement: Omega Calibre 1151 automatic chronograph

• Power Reserve: Approximately 44 hours

• Functions: Hours, minutes, small seconds, chronograph, day, date, month