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Seiko 5 Sports SRPJ85K1 Men's Watch – 36.4mm Black Dial Nylon
Ref. SRPJ85K1
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Stepping up in the same colour and case shape
The SRPJ85K1 sits at 36.4mm across a round stainless steel case 12.5mm deep, with a fixed steel bezel and a curved Hardlex crystal. The black dial carries subsidiary displays for day and date alongside the main time, with LumiBrite applied to both the hands and indices. The whole watch weighs 64g, which keeps it light through long wear. An 18mm green nylon strap with a pin buckle completes the build, sitting casually against the silver case. The 4R36 automatic movement supports hacking and hand-winding, and the case is rated to 100m water resistance.
- Reference
- SRPJ85K1
- Brand
- Seiko
- Case size
- 36.4mm
- Case material
- Stainless steel
- Case shape
- Round
- Dial
- Black
- Crystal
- Hardlex
- Movement
- Automatic
- Calibre
- 4R36
- Functions
- Day-date
- Water resistance
- 100m
- Bracelet / strap
- Fabric strap
- Strap colour
- Green
- Clasp
- Buckle
- 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.
Also in 4 collections
This watch appears in Stainless Steel Watches (2,946), Automatic Watches (1,744), Watches Under 37mm (1,504) and Automatic Watches Under £500 (301).
Manufacturer’s guarantee
What the specifications mean
A mechanical watch for everyday wear.
Strengths
- 100m water resistance covers swimming and watersports
- 36.4mm suits most wrists
- Luminous hands and markers for low light
- Sits in the lower half of Seiko's range as we list it
Price history
This watch is currently at its highest recorded price. It was £260 on 10 August. Prices are checked every day, and we record any changes.
Seiko 5 Sports SRPJ85K1 alternatives
Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.
| Specification | SRPJ85K1 | RGB10037/04 | EFK-200DG-5AER |
|---|---|---|---|
| Price | £290 | £289 | £360 |
| Case size | 36.4mm | 40mm | 38mm |
| Water resistance | 100m | 100m | 100m |
| Movement | Automatic | Automatic | Automatic |
| Strap | Fabric strap | Stainless steel bracelet | Stainless steel bracelet |
| Power reserve | — | — | 42 hours |
| 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.
Water resistance explainedWill the glass scratch?
It resists most everyday knocks. Hardlex is a hardened mineral glass — tougher than standard mineral, softer than sapphire.
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 comparedIs it a men's or women's watch?
Listed as men's, though at 36.4mm it sits in the range that suits anyone.
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.
Has the price changed recently?
It's currently at its highest recorded price. It's ranged between £260 and £290, today it's £290.
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