This replica Seamaster Diver 300M 210204 carries the 210.20.44.51.01.001 reference, placing it in the two-tone chronograph tier of the Seamaster Diver 300M family. The “210.20” prefix identifies this as a steel-and-gold construction, while the “44.51” portion signals the 44mm chronograph case. These are not subtle watches. The chronograph pushers, helium escape valve, and two-tone bracelet give this reference a visual density that time-only Seamasters do not have.

Case & Movement Specs

• Case diameter: 44mm
• Case material: stainless steel with sedna gold elements
• Bezel: ceramic, unidirectional, with gold diving scale
• Crystal: domed sapphire, anti-reflective on both sides
• Dial: black ceramic with wave pattern and three subdials
• Movement: automatic chronograph
• Functions: hours, minutes, seconds, chronograph, date

The sedna gold elements appear on the bezel ring, crown, chronograph pushers, and alternating bracelet links. Sedna is a proprietary alloy that holds its color longer than conventional rose gold because of its copper-palladium composition.

Caliber Breakdown

The chronograph module adds a column-wheel mechanism that controls the start, stop, and reset functions. Column-wheel chronographs are considered mechanically superior to cam-actuated systems because the pushers feel crisper and the engagement is more precise. Through the sapphire caseback you can see the decorated movement bridges, a Geneva wave pattern, and the co-axial escapement that reduces long-term wear on the pallet fork. For context on how this stacks up against the time-only variants, compare it to the 42mm Chronometer version in our Seamaster catalog.

How It Compares

Among the full Diver 300M range, the two-tone chronograph stands at the intersection of sport and luxury. It costs more than the steel-only versions and weighs more on the wrist because of the gold content. But the chronograph functionality makes it a genuine timing instrument, not just a diver with a date window. The 44mm case wears large, so buyers with wrists under 7 inches should try the 42mm time-only references first. This replica Seamaster Diver 300M 210204 puts the flagship chronograph configuration within reach.