Omega Seamaster Diver 300M Co-Axial Mens Watch
10 % below RRP
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ℹ️ 1-month trend
Price change over the past 30 days. Shows the short-term market movement — relevant if you want to buy or sell soon.
ℹ️ 4-month trend
The central metric behind the momentum score. It filters out short-term swings and shows the true, medium-term market trend of this reference.
ℹ️ Volatility
Annualised price fluctuation. Below 10 % = very stable, 10–20 % = normal, above 20 % = volatile. With high volatility the price can change quickly — in both directions. Be cautious about buying without checking the current price.
ℹ️ Momentum score
ChronoCheck's own indicator from 0 to 100, calculated from the 4-month trend, volatility and market direction.
- Above 60 — Upward trend. Good time to sell, prices are rising.
- 40 – 60 — Neutral. Stable price level, no pressure to act.
- Below 40 — Downward trend. Wait or enter at a good price.
ℹ️ Investment Grade A/B/C/D
ChronoCheck's own rating for each reference. A 0–100 point scale, made up of four weighted components:
- Momentum (40 pts) — trend strength from the momentum score.
- Liquidity (25 pts) — number of active live listings.
- Stability (20 pts) — inverse volatility — the calmer, the better.
- Source robustness (15 pts) — number of independent market sources.
- A · 75+ Trend is right, liquidity good, data broad.
- B · 55–74 Solid, but one component weaker.
- C · 35–54 Average, volatility or market breadth weigh on it.
- D · below 35 Downward or too little data — a collector's piece.
Not investment advice. Pure data analysis from aggregated market sources.
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Technical data
Omega Ref. O21030422006001 — Variants and collector names
Known as: Grey Dial SD300M, Rhodium Grey Diver, Grey Ghost
Production phases and changes
- 2018: Introduction of the 2018 generation: case 41→42mm, Cal. 8507→8800 METAS Master Chronometer, new ceramic dial with laser wave pattern, ceramic bezel with white enamel scale (replacing aluminum), sapphire display caseback
Movement variants
- 8800 (2018–today) · 25200 bph
Bezel variants
- SD300M-42-Keramik-Blau-WeißEmail-60min "Blue Ceramic White Enamel Diver"
Dial variants
- Rhodium Grey Ceramic Dial — Laser-engraved wave pattern, polished raised steel appliqués with white Super-LumiNova, date 6h, no text on dial
Crystal variants
- Saphir-gewoelbt-AR-beidseitig-SD300M-42
Bracelet variants
- 3-reihiges Stahl-Oyster-Armband (polierter Mittelteil, gebürstete Außenglieder) Ref. SD300M-42-3Link-Stahl-2018
- Seamaster Diver 300M gebürstetes Edelstahl-Meshband (No-Date 2024) Ref. SD300M-Mesh-SS-2024
Reference 210.30.42.20.06.001 doesn't appear as "Grey Ghost" in any Omega catalog. Collectors coined that name themselves, along with "Rhodium Grey Diver" or simply "Grey Dial SD300M" — three nicknames for the same watch, none of them from Omega. That says more about the fan base than about the reference itself.
## Baselworld 2018, Three Colors, One Leap Forward
Omega unveiled a complete overhaul of the Seamaster Diver 300M in 2018: the case grew from 41 to 42 millimeters, Caliber 8507 gave way to the METAS-certified Caliber 8800, and the aluminum bezel was replaced by ceramic. Three color variants launched simultaneously — black under reference code 01, blue under 03, grey under 06. The previous 212.30.42.20.xx.001 series was fully replaced, not supplemented.
## A Ceramic Dial Instead of Lacquered Brass
The dial carries the internal designation SD300M-42-Grey-Ceramic-Wave-Steel-Date and is made from rhodium-plated grey ceramic with a laser-engraved wave pattern, replacing the earlier lacquered version. The bezel, listed under the code SD300M-42-Ceramic-Blue-WhiteEnamel-60min, pairs a ceramic body with a white enamel scale instead of the previous aluminum insert — a material shift that has run through Omega's entire Diver 300M line since 2018.
## The Caliber That Makes the Difference
Caliber 8800 sits behind a sapphire caseback and carries METAS Master Chronometer certification, something the previous generation's Caliber 8507 lacked. For buyers, that's the quickest way to tell old and new generations apart just by looking at the case back.
If you're looking to buy or sell a 210.30.42.20.06.001, get in touch with us for a market value assessment.
Brand profile: Omega
Omega is the second most counterfeited Swiss watch brand. The Speedmaster and Seamaster are especially targeted. Pay close attention to movement details (Co-Axial) and dial textures.
- Speedmaster: The chronograph reset hand must snap back precisely to 12 o'clock — fakes stop 1–3 seconds off or wobble
- Speedmaster (Hesalite): The Omega logo is micro-laser-etched on the UNDERSIDE of the Hesalite crystal — only visible at a specific angle and in the right light — fakes omit it or place it incorrectly
- Seamaster: The wave-pattern dial must be ENGRAVED (tactile relief) — printed/flat wave lines = fake
- DON (Dot Over Ninety): small dot ABOVE the '90' on the Speedmaster tachymeter bezel — position/size often wrong on fakes
Serial number format: Omega serial number: 8-digit number on the caseback or between the lugs (on older models). Since ~2018 engraved on the caseback at 6 o'clock. Format: purely numeric. Verifiable on the Omega website with an extract from the archive.
Further sources
Buying guide: Omega Seamaster Diver 300M Co-Axial Mens Watch
Entry into Omega
At $6,818 this reference is one of the more affordable ways to wear a Omega on your wrist. That is precisely why many pieces have already passed through several hands — condition varies accordingly. Buyers here should pay particular attention to service history and honest photos from the seller.
What to look out for when buying?
- Authenticity: The serial number and reference on the case must match the papers. A professional authenticity check of the Omega Seamaster Diver 300M Co-Axial Mens Watch reliably rules out counterfeits.
- Condition: Check scratches on the case and bezel — professional refurbishment can leave traces.
- Service history: A documented service by the manufacturer or a certified watchmaker increases the value.
- Scope of delivery: Box, papers and warranty card make a noticeable price difference on the Seamaster Diver 300M Co-Axial Mens Watch.
- Independent certification: The CPS-52 standard covers 52 checkpoints — from the serial number and the timing machine to water resistance. The result is secured on the blockchain and can be verified at any time.
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