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1Repair Windows errors before they cause bigger problems2Scan for outdated or missing drivers - takes under a minute3Clear out junk files and repair common Windows errorsThe Tudor North Flag 91210N pairs a 40 mm steel case with the manufacture MT5621 automatic movement, a COSC-certified calibre rated for about 70 hours of power reserve. Its power-reserve display and sharply instrument-like dial make it unusually functional-looking for a Tudor of its era. It is a discontinued model according to secondary coverage, so the practical question today is less about launch pricing and more about whether a particular pre-owned example is complete and in good condition.
What the Tudor North Flag 91210N is
The North Flag reviewed here is reference 91210N, a 40 mm watch in satin-finished 316L stainless steel. Time+Tide describes a matte black dial framed by a double bezel in steel and matte black ceramic. Period configurations included a steel bracelet or a black leather strap with yellow stitching and lining. Time+Tide’s hands-on review lists the model’s design and specifications.
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The dial’s most distinctive feature is a power-reserve display, paired with an instantaneous date. Yellow details give the otherwise black-and-steel design an instrument-panel character. Whether that contrast feels purposeful or too conspicuous is a matter of taste; the display and accents themselves are documented design features, not performance claims.
What is special about the MT5621 movement?
The MT5621 is an automatic manufacture movement with COSC certification, a silicon balance spring and a variable-inertia balance. Hodinkee reports its dimensions as 33.8 mm by 6.5 mm and its frequency as 28,800 vibrations per hour (4 Hz). The specified power reserve is 70 hours; Time+Tide describes it as approximately 70 hours. Hodinkee’s review details the calibre and its role in the watch.
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- Tudor Royal Automatic Salmon Dial Men's Watch M28600-0009
The reserve display gives the movement specification a visible purpose: it lets the wearer see roughly how much running time remains before the watch needs winding or wearing again. Hodinkee found the display useful and described the movement’s visible appearance as functional rather than conventionally decorative. Those are the publication’s assessments, not a universal ranking of movement finishing.
Tudor’s general explanation of its manufacture calibres provides broader context on its movements and COSC certification, but does not change the 91210N’s model-specific figures. See Tudor’s manufacture movement overview.
Rank #2
- 41mm steel case with polished and satin finish
- Bidirectional rotatable bezel in steel with 24-hour graduated anodised aluminium disc
- Self-winding mechanical movement with 70 hour power reserve
How it wears and what the design does well
Hodinkee describes the integrated case-and-bracelet feel as comfortable and the power-reserve indicator as genuinely useful. The combination of a 40 mm steel case, dark bezel and matte dial keeps the overall layout restrained, while the yellow accents and reserve display make it visually distinct. The design is a good fit for someone who wants a technical, legible-looking watch rather than a traditional dress-watch dial; the prominent details may be less appealing if you prefer a minimal face.
Do not confuse it with the current Northflag
Tudor’s current Northflag family page describes a different watch, with a GMT function and MT5652-U calibre. That model is specified at 65 hours of reserve and has a two-link bracelet with T-fit rapid adjustment, monobloc ceramic luminous markers and a 24-hour graduated rehaut. Those details do not belong to the older 91210N with MT5621. Tudor’s Northflag family page covers the current model.
Rank #3
- Water resistance depth: 100.0 meters
- Case diameter: 38.0 millimeters
- Item shape: Round
- Department name: mens
- Calendar type: Date
Is the Tudor North Flag discontinued?
WatchCharts characterizes reference 91210N as discontinued in its retrospective coverage. The sources cited here do not establish a formal Tudor discontinuation announcement or current stock availability, so treat “discontinued” as secondary coverage rather than confirmation of an official announcement. For a prospective buyer, availability and price depend on the specific pre-owned listing.
What to check when buying a pre-owned 91210N
Because condition and completeness vary from one used watch to another, evaluate the actual example rather than relying on a generic listing headline. Confirm the reference and configuration, then ask for clear evidence of condition and ownership history.
Rank #4
- .Hand-stitched with high-strength nylon thread, it is sturdy and less likely to crack
- Easy to install and replace without tools
- Special surface treatment, resistant to daily splashing water and sweat erosion.
- Skin-friendly leather inner layer, no indentation after long-term wearing
- Worry free after-sales service: We provide a "180 day worry free replacement" service. Is the strap fading? Does the texture not match? If there is no human damage, we will replace it directly! If you need customization, please contact customer service. Welcome to your purchase
- Reference and movement: Confirm the watch is reference 91210N with the MT5621, not the newer GMT Northflag.
- Bracelet or strap: Check whether the listing includes the steel bracelet or the original black leather strap with yellow details, and whether the included configuration matches the seller’s description.
- Condition: Request detailed images of the case, bezel, dial, crystal and bracelet or strap, and ask about damage or prior polishing.
- Service history: Ask for available service records and clarify what is documented versus what the seller merely reports.
- Completeness: Check which box, papers and accessories are actually included; do not assume they come with the watch.
- Price context: Compare current listings for similar condition and completeness. Time+Tide reported launch-era prices of CHF 3,400 on leather and CHF 3,500 on steel, including VAT; those historical figures are not a current valuation.
A black leather strap with yellow stitching and lining was an original configuration, but the cited coverage does not establish strap dimensions or third-party replacement compatibility. Verify fit for the specific watch before buying a replacement.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Verdict: is the Tudor North Flag a good watch?
The 91210N is compelling if you want a 40 mm steel Tudor with a COSC-certified in-house movement, approximately 70 hours of reserve and a visible power-reserve display. Its instrument-like dial is more distinctive than a conventional black watch, and the reserve indicator connects the movement’s capability to the everyday experience. The main trade-off is aesthetic: yellow accents and an exposed reserve display are defining features, not details that disappear into the background. On the used market, the individual watch’s condition, service evidence and included configuration matter more than its original launch price.
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Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
