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Longines HydroConquest 42mm Mens Watch Black
Ref. L37884566
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Stepping up in the same colour and case shape
The HydroConquest has always occupied an interesting position in Longines' catalogue — serious enough for actual dive use, restrained enough to leave the sport watch theatrics to others. This iteration carries a redesigned dial and bezel, and the changes read as refinement rather than reinvention: a polished black lacquered surface, a ceramic bezel insert that resists scratching in a way that anodised aluminium simply does not, and applied indices that give the dial some physical depth. At 11.7mm thick for a watch rated to 300 metres, it wears noticeably flatter than most in this class, which means it moves under a cuff without catching and sits closer to the wrist than the depth rating might lead you to expect. The bracelet's micro-adjustment system is the kind of detail that sounds minor until you have lived with a dive bracelet that only fits right at one end of its adjustment range — this one can be dialled in precisely without tools. The L888.5 is built around a silicon balance spring, which takes the movement well beyond the standard antimagnetic threshold and keeps it running accurately in environments — near speakers, airport scanners, MRI suites — where a conventional spring would suffer. The 72-hour power reserve is a practical bonus for anyone who rotates between watches.
- Reference
- L37884566
- Brand
- Longines
- Collection
- HydroConquest
- Case size
- 42mm
- Case thickness
- 11.70mm
- Lug width
- 21mm
- Case material
- Stainless steel
- Case shape
- Round
- Dial
- Black
- Crystal
- Sapphire
- Bezel
- Unidirectional rotating
- Movement
- Automatic
- Calibre
- ETA A31.L11
- 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
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.
Manufacturer’s guarantee
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.
Will the glass scratch?
Unlikely. Sapphire is second only to diamond in hardness and shrugs off everyday marking.
Does it need a battery?
No. It is automatic — the motion of your wrist winds it, and there is no cell to replace.
How 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.
Is it a men's or women's watch?
Listed as men's.
Cheapest place to buy
Goldsmiths is the only UK retailer we track stocking this reference, so there is nothing to compare it against today.
Who are Goldsmiths?
Goldsmiths has been selling watches in Britain since 1778 and is part of the Watches of Switzerland Group, which is listed on the London Stock Exchange. They are an authorised dealer, so a watch comes with the manufacturer’s own warranty.
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