Heron Watch Co band size chart: one width for the whole catalog, and that is the point
Every watch Heron sells takes a 20mm strap, including the watches that look like they should not. The 39mm Marinor diver, the 37.5mm Mirabel GMT and the 37mm Continental all print the same line, Lug Width: 20mm, in the same Dimensions block, on every one of the 37 watch pages in the brand's catalog [2]. A buyer who assumes a small watch takes a small strap, the way most size charts imply, will order an 18mm strap for a Mirabel and be wrong. This page exists to confirm the exception-free answer, model by model, because nobody else has: Heron publishes no size guide of its own [8].
Scope, stated up front
The Heron store's product sitemap lists 62 product handles and the product feed carries exactly the same 62 rows, zero delta in either direction [1]. Of those 62, exactly 37 are watches; the other 25 are straps (FKM rubber, sailcloth, hybrid leather and NATO products), excluded from the watch census and used only as corroborating evidence below. Every one of the 37 watch rows carries the verbatim line Lug Width: 20mm inside its Dimensions block [2]. Nothing on this page was taken from a lug-to-lug figure, a strap product listing read backwards, or the nearest round number.
The chart, class by class
| Family | Case diameter | Lug width | Attested how |
|---|---|---|---|
| Marinor, 300-meter class (20 pages) | 39mm | 20mm | Dimensions Case Size: 39mm (Diameter) X 47mm (Lug To Lug) Lug Width: 20mm Thickness: 12.9mm (11.3mm w/o Crystal), quoted verbatim and rendered fresh [3]. All 20 pages identical: Nautilus, Pequod, Dutchman, Drakkar, Ghost, both Seastorm Blacks, both Yellowtails, the four Captains, Sea Ranger, Sea Urchin, Navy Seal, Maelstrom, Coral Reef, Bahamas and Argo |
| Marinor, 250-meter class (8 pages) | 39mm | 20mm | Case Size: 39mm (Diameter) X 46mm (Lug To Lug) Lug Width: 20mm [4]. All 8 pages identical: Atlantic Blue, Caribbean Blue, Gilt & Black, Menthol Green and the four Rainbow variants. Same diameter as the 300-meter class, 1mm less lug-to-lug, same width |
| Mirabel and Mirabel GMT (6 pages) | 37.5mm | 20mm | Dimensions Case Size: 37.5mm (Diameter) X 43.5mm (Lug To Lug) Lug Width: 20mm Thickness: 10mm (12mm with Boxed Crystal), quoted verbatim and rendered fresh [5]. All 6 pages print the width line identically; 5 of 6 print the block above character for character, the Brown GMT alone dropping the mm on the thickness figure (Thickness: 10 instead of 10mm): the Firehorse three-hander and the five GMTs (White, Black, Blue, Brown, Cigar Club) |
| Continental (3 pages) | 37mm | 20mm | Diameter: 37mm (wears like 39mm) Lug to Lug: 43mm Lug Width: 20mm Case Thickness: 8.5mm [6]. All 3 pages carry the same numbers; the Black and Blue print a stray space inside the number, 3 7mm, worth knowing before anyone calls it a typo in the width, and the Black also lowercases the length label (Lug to lug). It is not: the width line is clean on every page |
Four dimension templates carry all 37 watches, and the width line is the same in every one of them: 37 of 37 watch pages print Lug Width: 20mm, recomputed from the census and not counted by eye [2]. The rows above split the Marinor family into its two dimension classes because the classes differ in lug-to-lug (47mm versus 46mm) and water resistance, not because they differ in width. No page in the catalog prints 18mm, 19mm, 21mm or 22mm at the lugs.
The trap: small case, standard lugs
Width charts usually track case size, and most catalogs under 39mm drop to 18mm lugs, so the reflex guess for a 37.5mm dress watch is an 18mm strap. Heron breaks the reflex in both directions at once: the Mirabel GMT at 37.5mm and the Continental at 37mm, the two smallest cases in the catalog, sit on the same 20mm lug spacing as the 39mm, 300-meter Marinor diver [5] [6]. The Continental page even prints the diameter as 37mm (wears like 39mm) [6], and that wears-like number is a case-size statement only; it never touches the width column here. If the watch is a Heron and it is not a strap product, the strap is 20mm.
What the numbers that are not widths say
Every Heron Dimensions block prints a length over the lugs next to the width, and mixing the two is the standard way inherited size charts get this class of catalog wrong. The 300-meter Marinors print 47mm (Lug To Lug), the 250-meter Marinors 46mm, the Mirabels 43.5mm and the Continentals 43mm [3] [4] [5] [6]. All four are lengths, none is a strap size, and none appears in the width column of the table above. The same discipline applies to the strap shop: the FKM rubber strap page prints Dimensions: 20mm width Elegantly tapers to 18mm at buckle [7], and that 18mm is a taper to the buckle on a 20mm strap, quoted here as its own topic precisely so it is never read as a watch width. The Mirabel pages print their leather lengths as 125/75mm, which are strap half-lengths, not widths.
The strap shop confirms the census
Every strap Heron sells is built for the one width. All 25 strap products in the feed are 20mm-at-the-lugs products: the ten FKM and tropical rubber straps, the five sailcloth and hybrid sailcloths, the seven NATO straps and the three hybrid leathers [7]. The store sells no 18mm watch and no 18mm strap; the only 18mm anywhere in the strap rows is the buckle end of the rubber and sailcloth tapers. A buyer who trusts the brand's own accessory shelf reaches the same answer as the census: one width, no exceptions.
Why no incumbent chart exists
Heron publishes no size guide. The site's pages index holds exactly twelve pages, about-us, contact-us, heron-bespoke, servicing, showroom, warranty, lookbook, newsletter-sign-up, sign-up, the 2027 price-increase notice, an affiliate placeholder and a how-to-set-a-GMT-watch tutorial, none of them a fitting or strap guide [8]. Third-party coverage exists but stops short of a catalog chart, and should be disclosed as partial: review coverage of single models (the Marinor launch coverage and the Mirabel GMT reviews quote 20mm for the one watch under review), a specs tracker carries the Mirabel GMT at 20mm, and a strap retailer's blog post covers the brand but lists model names that do not exist in the brand's own 62-row catalog, with a thickness and a depth rating that match no Heron page. None of that is a whole-catalog table, and some of it is wrong where it can be checked. The watchbands.ai brand index, pulled fresh for this build with its Seiko, Citizen and Rolex controls firing across 193 brands (189 by this page's own recount at second-eyes time), does not list Heron at all [9]. The confirmation table below the fold on this page is the first complete one.
How this chart was checked
At build time, 1 October 2026, the product feed was re-pulled fresh (62 rows, raw sha16 f58b36ee444262db) and the 37-of-37 watch census re-run against it [2]. The sitemap was re-pulled with its from and to parameters and re-matched handle for handle against the feed, 62 against 62, zero delta in either direction [1]. Three product pages were rendered fresh as a control, one Mirabel, one Marinor and one Continental, and each printed its Lug Width: 20mm line server-rendered verbatim [3] [5]. Every quotation on this page was machine-matched as a contiguous run against the bytes it came from, and every count in every sentence was recomputed from the final census rather than counted by eye. For the brand universe around it, the watch band size chart carries Heron beside every other brand charted here, and the lug width chart by brand holds the expanded per-brand table.
Sources
- heronwatches.com sitemap index, pulled fresh at build time: the products sitemap (with its from and to parameters) lists 62 product handles, exactly matching the 62 rows of the product feed, zero delta in either direction
- heronwatches.com products.json feed, pulled fresh at build time (raw sha16 f58b36ee444262db): 62 products, of which 37 are watches and every watch row carries the line Lug Width: 20mm inside its Dimensions block; the other 25 rows are straps
- Marinor Nautilus product page, rendered fresh at build time: Dimensions Case Size: 39mm (Diameter) X 47mm (Lug To Lug) Lug Width: 20mm Thickness: 12.9mm (11.3mm w/o Crystal). The 300-meter Marinor class prints this block on all 20 of its pages
- Marinor Atlantic Blue product page, feed row pulled fresh at build time: the 250-meter Marinor class prints Case Size: 39mm (Diameter) X 46mm (Lug To Lug) Lug Width: 20mm on all 8 of its pages, the four Rainbow variants included
- Mirabel Firehorse product page, rendered fresh at build time: Dimensions Case Size: 37.5mm (Diameter) X 43.5mm (Lug To Lug) Lug Width: 20mm Thickness: 10mm (12mm with Boxed Crystal). All six Mirabel pages, the Firehorse and the five GMTs, print the identical width line; five of the six print the whole block verbatim, the Brown GMT dropping the mm on the thickness figure
- Continental Cream product page, feed row pulled fresh at build time: Diameter: 37mm (wears like 39mm) Lug to Lug: 43mm Lug Width: 20mm Case Thickness: 8.5mm. All three Continental pages print the line, the Black and Blue with a stray space inside the number (3 7mm), the Black also lowercasing the length label
- the brand's own FKM rubber strap product, feed row pulled fresh at build time: Dimensions: 20mm width Elegantly tapers to 18mm at buckle. All 25 strap rows in the store are 20mm-at-the-lugs products; the taper is quoted here as its own topic, never as a watch width
- heronwatches.com pages sitemap, pulled fresh: twelve pages (about-us, contact-us, heron-bespoke, servicing, showroom, warranty, lookbook, newsletter-sign-up, sign-up, a 2027 price-increase notice, an affiliate placeholder and a GMT-setting tutorial). No size guide, no strap guide, no fitting page of any kind. The how-to-set-a-GMT tutorial was rendered and checked: it covers movement setting only, with no strap, lug or width content
- watchbands.ai brands index, fresh pull at build time (193 brands, Seiko, Citizen and Rolex controls firing; Heron absent by slug and by whole-word text match)