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Longines HydroConquest 41mm Mens Watch Green Stainless Steel
Ref. L37904066
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Stepping up in Longines's range
The HydroConquest began as a straightforward sports diver, but this variant extends it into a second time zone — the L844.5 underneath is a genuine GMT movement, with an independently adjustable local hour hand that can be set forward or back without stopping the watch or disturbing the running seconds. That mechanism sits on a silicon balance spring, which sidesteps the magnetic interference that catches a lot of travel watches out in airports and on aircraft. At 41mm across and 49.4mm lug to lug, it sits well inside the threshold where a diver starts to feel cumbersome on average wrists, and at 12.9mm it is flatter than the rating might suggest. The green dial runs with applied round and baton markers rather than the chunky Arabic numerals of earlier HydroConquest models — a quieter read, better suited to something worn through a working day as well as near water. The polished ceramic bezel insert holds its finish better than steel under daily use. The bracelet has been meaningfully updated: tapered links, a double-security clasp, and a toolless micro-adjustment system built into the clasp itself. At 181.4 grams it has presence on the wrist, but the fit can be dialled in without a watchmaker, which matters more the further from home you are.
- Reference
- L37904066
- Brand
- Longines
- Collection
- HydroConquest
- Case size
- 41mm
- Case thickness
- 12.9mm
- Lug width
- 21mm
- Case material
- Stainless steel
- Case shape
- Round
- Dial
- Green
- Crystal
- Sapphire
- Bezel
- Rotating
- Movement
- Automatic
- Calibre
- L844
- Functions
- GMT, Date
- Water resistance
- 300m
- Bracelet / strap
- Stainless steel bracelet
- Strap colour
- Silver
- Clasp
- Folding clasp
- Lume
- Luminous
- Retailer
- Mappin & Webb
Additional specifications
- Lug-to-lug
- 49.4mm
- Power reserve
- 72 hours
Learn more about Longines
Auguste Agassiz began trading watches in Saint-Imier in 1832, but the modern company dates from 1860, when his nephew Ernest Francillon built a factory in the meadows beside the Suze — the longines of the local dialect — and consolidated the scattered outworkers of the region under one roof.
Longines registered its winged hourglass in 1889. It is the oldest watch trademark still in continuous use.
The company's identity was built on precision and on timing things in public. It supplied chronographs for the first modern Olympic events it timed in 1896, timed the 1912 Federal Gymnastics Festival with a broken-wire mechanism accurate to a hundredth of a second, and developed the photo-finish camera and the quartz timing devices used across twentieth-century athletics.
Its aviation associations are equally deep. Longines instruments were carried by Charles Lindbergh across the Atlantic in 1927, and the Hour Angle watch, designed to Lindbergh's own specification to simplify longitude calculation, remains in the catalogue. Amelia Earhart and Howard Hughes both navigated by Longines.
The house was among the most decorated at nineteenth-century observatory trials, holding numerous precision records. Since joining the Swatch Group in 1983 it has occupied the accessible-heritage position: exclusive ETA-based movements, archive-driven designs through the Heritage line, and volume that makes it one of the group's most important brands.
- 1860
- Ernest Francillon builds the factory at Les Longines.
- 1889
- The winged hourglass is registered — the oldest watch trademark in use.
- 1912
- Broken-wire timing achieves hundredth-second accuracy.
- 1927
- Lindbergh crosses the Atlantic with Longines instruments.
- 1983
- Becomes part of the Swatch Group.
Also in 7 collections
This watch appears in the Longines HydroConquest range (42), Back in Stock (3,734), Stainless Steel Watches (2,581), Automatic Watches (1,570), Sports Watches (707), Dive Watches (505) and Green Dial Watches (343).
What the specifications mean
A mechanical watch built to be worn hard and got wet.
Strengths
- 300m water resistance, rated for actual diving
- Sapphire crystal, which resists scratching
- 72-hour reserve survives a weekend off the wrist
- Luminous hands and markers for low light
- Second time zone for travelling
Longines HydroConquest alternatives
Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.
| Specification | L37904066 | 129369 | R32154208 |
|---|---|---|---|
| Price | £2,650 | £3,000 | £2,500 |
| Case size | 41mm | 41mm | 42mm |
| Water resistance | 300m | 300m | 300m |
| Movement | Automatic | Automatic | Automatic |
| Strap | Stainless steel bracelet | Stainless steel bracelet | Titanium bracelet |
| Power reserve | 72 hours | — | 80 hours |
| This watch |
| Closely matched |
Your new watch
Frequently asked questions, and things you should know about this watch
Can I swim with it?
Yes. At 300m it is rated for swimming, snorkelling and recreational diving.
Water resistance explainedWill the glass scratch?
Unlikely. Sapphire is second only to diamond in hardness and shrugs off everyday marking.
Sapphire, mineral and acrylic comparedDoes it need a battery?
No. It is automatic — the motion of your wrist winds it, and there is no cell to replace.
Quartz, automatic and solar comparedHow long does it run for when it's not worn?
About 72 hours fully wound — enough to sit off the wrist over a weekend and still be running.
What size strap does it take?
21mm. Any strap of that width will fit, and on most modern watches quick-release bars make the swap a two-minute job with no tools.
Will it fit my wrist?
Lug-to-lug is 49.4mm, which suits wrists from roughly 16.5cm (6½ inches) upward.
Lug-to-lug decides fit more than case diameter does.
How to size a watch to your wristIs it a men's or women's watch?
Listed as men's.
Cheapest place to buy
Mappin & Webb is the only UK retailer we track stocking this reference, so there is nothing to compare it against today.
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