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Longines HydroConquest 39mm Mens Watch Black
Ref. L37794566
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Stepping up in the same colour and case shape
The HydroConquest has been Longines's working diver since the 1960s, and this 39mm version represents a considered refinement of that lineage rather than a reinvention of it. The oversized Arabic numerals of earlier generations are gone, replaced by applied dot and baton indices that read as rather more composed on the wrist — a dial that suits the watch's proportions without sacrificing anything in low light. At 11.7mm thick, it sits unusually flat for a watch rated to 300 metres, which means it passes under a cuff in a way that most divers at this depth rating simply will not. The 39mm diameter puts it at the quieter end of the sport-watch market, and it wears accordingly — closer to a capable everyday watch than something that announces itself. The L888 is the movement worth knowing about here. Built on an ETA base but substantially reworked by Longines, it runs at 3.5 Hz rather than the standard 4 Hz, which is what buys the 72-hour power reserve. The silicon balance-spring adds genuine anti-magnetic resilience and contributes to the stability that earns it Longines's five-year guarantee — extended specifically because they trust this movement to earn it.
- Reference
- L37794566
- Brand
- Longines
- Collection
- HydroConquest
- Case size
- 39mm
- Case thickness
- 11.7mm
- Case material
- Stainless steel
- Case shape
- Round
- Dial
- Black
- Crystal
- Sapphire
- Bezel
- Unidirectional rotating
- Movement
- Automatic
- Calibre
- L888
- Functions
- Date
- Water resistance
- 300m
- Bracelet / strap
- Stainless steel bracelet
- Strap colour
- Silver
- Clasp
- Folding clasp
- Lume
- Super-LumiNova
- Retailer
- Goldsmiths
Additional specifications
- Power reserve
- 72 hours
- Warranty
- 5 years
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 6 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) and Dive Watches (505).
Manufacturer’s guarantee
What the specifications mean
A mechanical watch built to be worn hard and got wet.
Strengths
- 300m water resistance, rated for actual diving
- 39mm suits most wrists
- Sapphire crystal, which resists scratching
- 72-hour reserve survives a weekend off the wrist
- Luminous hands and markers for low light
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 | L37794566 | YA136365 | R32223213 |
|---|---|---|---|
| Price | £1,925 | £1,890 | £2,200 |
| Case size | 39mm | 40mm | 39mm |
| Water resistance | 300m | 300m | 300m |
| Movement | Automatic | Automatic | Automatic |
| Strap | Stainless steel bracelet | Fabric strap | Stainless steel bracelet |
| Power reserve | 72 hours | 38 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.
Is it a men's or women's watch?
Listed as men's, though at 39mm it sits in the range that suits anyone.
Cheapest place to buy
Goldsmiths is the only UK retailer we track stocking this reference, so there is nothing to compare it against today.
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