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Seiko Prospex SFJ003P1 'Black On Black' Solar Speedtimer Watch - W25437
Ref. SFJ003P1
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Stepping up in the same dial colour
The Speedtimer line traces its DNA directly to the timing instruments Seiko built for professional athletics — the brand has been World Athletics' official timekeeper since 1985, and the SFJ003P1 makes that heritage readable in the layout of its dial. Rather than grouping the chronograph sub-dials around a conventional arrangement, Seiko separates them entirely: time-of-day sits at 6 o'clock in isolation, while three independent chronograph registers — running to 1/100th of a second — occupy the upper half of the dial. It is the logic of a timing panel translated into a wristwatch, and it reads accordingly. At 42mm the case sounds substantial, but a 48.3mm lug-to-lug measurement means it sits closer to the wrist than that diameter implies, and the 12.9mm profile keeps it from stacking too high under a cuff. The 152g weight is felt — this is not a watch that disappears on the wrist — and the hammer-shaped pushers add to the sense of purpose: they are sized to be hit cleanly, not delicately. The 8A50 solar calibre carries a six-month power reserve and holds to within ±15 seconds per month, which is among the tighter tolerances available in solar quartz. Charge it occasionally and it asks very little else.
- Reference
- SFJ003P1
- Brand
- Seiko
- Collection
- Speedtimer
- Case size
- 48.3mm
- Case material
- Stainless steel
- Case shape
- Round
- Dial
- Black
- Crystal
- Sapphire
- Movement
- Solar
- Calibre
- 8A50
- Functions
- Chronograph, Stopwatch, Solar powered, Dual display
- Water resistance
- 100m
- Bracelet / strap
- Stainless steel bracelet
- Strap colour
- Silver
- Clasp
- Three-fold clasp
- Lume
- LumiBrite
- Retailer
- F.Hinds
Learn more about Seiko
Kintaro Hattori opened a watch and clock shop in Tokyo in 1881, aged twenty-one, and began manufacturing under the name Seikosha — roughly, house of exquisite workmanship — in 1892. The Seiko name appeared on watches from 1924.
The company's significance is that it broke the Swiss monopoly twice. First on precision: Seiko was appointed official timekeeper of the 1964 Tokyo Olympics and built the quartz chronometers and printing timers to do it, and in the 1960s its movements placed highly at the Neuchâtel and Geneva observatory trials against the best Swiss houses.
Then on technology. On Christmas Day 1969 Seiko released the Astron, the world's first quartz wristwatch, accurate to five seconds a month where mechanical watches managed that per day. The consequences for Switzerland were catastrophic — employment in the Swiss industry fell by roughly two-thirds over the following decade. Seiko deliberately did not enforce its quartz patents, allowing the technology to spread.
The same year it produced the 6139, among the first automatic chronographs, and it has since introduced Kinetic, Spring Drive — a hybrid regulating a mechanical mainspring electronically, giving a perfectly gliding seconds hand — and its own dive and field lines.
Seiko remains fully vertically integrated, making its own hairsprings, quartz crystals, and even the Zaratsu-polished cases, at price points from under a hundred pounds upward.
- 1881
- Kintaro Hattori opens his Tokyo shop.
- 1924
- The first watches carry the Seiko name.
- 1964
- Official timekeeper of the Tokyo Olympics.
- 1969
- The Astron becomes the first quartz wristwatch.
- 1999
- Spring Drive enters production.
Manufacturer’s guarantee
What the specifications mean
Strengths
- 100m water resistance covers swimming and watersports
- Sapphire crystal, which resists scratching
- Luminous hands and markers for low light
Worth knowing
- 48.3mm is a large watch with real presence
Compare alternatives
Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.
| Specification | SFJ003P1 |  010-02935-50 |  ECB-2300HR-1AER |
|---|---|---|---|
| Price | £469 | £439 | £389 |
| Case size | 48.3mm | 50mm | 45.8mm |
| Water resistance | 100m | 100m | 100m |
| Movement | Solar | Solar | Solar |
| Strap | Stainless steel bracelet | Silicone strap | Leather strap |
| This watch |
|
|
Your new watch
Frequently asked questions, and things you should know about this watch
Can I swim with it?
Yes. At 100m it is rated for swimming and snorkelling, though not for 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 charges from light, and the cell behind that is designed to last a decade or more.
Is it a men's or women's watch?
Listed as men's.
Cheapest place to buy
F.Hinds is the only UK retailer we track stocking this reference, so there is nothing to compare it against today.
Who are F.Hinds?
F.Hinds has been run by the same family since 1856 and is now in its fifth generation, with more than 115 shops across England and Wales. They are a member of the Responsible Jewellery Council and an Authorised Diamond Dealer.
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