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Seiko 5 Sports 42mm Mens Watch
Ref. SRPD51K1
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Stepping up in the same colour and case shape
The SRPD51K1 wears its 42.5mm stainless steel case on a matching three-link bracelet secured by a three-fold clasp with push-button release. The blue sunburst dial carries day and date at three o'clock, with a unidirectional rotating bezel in a matching blue insert adding to the sports brief. The crown sits recessed at four o'clock, and a screw-down exhibition case back reveals the 4R36 movement beneath. Hands and indices carry a heavy LumiBrite coating. At 13.4mm thick with a 46mm lug-to-lug span, it sits with some presence on the wrist. Water resistance stands at 100 metres.
- Reference
- SRPD51K1
- Brand
- Seiko
- Case size
- 42.5mm
- Case thickness
- 13.4mm
- Case material
- Stainless steel
- Case shape
- Round
- Dial
- Blue
- Crystal
- Hardlex
- Bezel
- Unidirectional rotating
- Movement
- Automatic
- Calibre
- 4R36
- Functions
- Date
- Water resistance
- 100m
- Bracelet / strap
- Stainless steel bracelet
- Strap colour
- Silver
- Clasp
- Three-fold clasp
- Lume
- LumiBrite
- Retailer
- F.Hinds
Additional specifications
- Lug-to-lug
- 46mm
- Power reserve
- 41 hours
- Weight
- 170g
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 6 collections
This watch appears in Back in Stock (3,434), Stainless Steel Watches (2,782), Automatic Watches (1,540), Blue Dial Watches (758), Automatic Watches Under £500 (306) and Watch Price Drops (255).
Manufacturer’s guarantee
Best of 3 retailers
What the specifications mean
A mechanical watch for everyday wear.
Strengths
- 100m water resistance covers swimming and watersports
- 46mm lug-to-lug keeps the 42.5mm case wearable
- 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 lowest recorded price. It reached £290 on 13 September. Prices are checked every day, and we record any changes.
Seiko 5 Sports alternatives
Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.
| Specification | SRPD51K1 | R8823118012 | RGB10007/05 |
|---|---|---|---|
| Price | £280 | £299 | £299 |
| Case size | 42.5mm | 42mm | 43mm |
| Water resistance | 100m | 100m | 100m |
| Movement | Automatic | Automatic | Automatic |
| Strap | Stainless steel bracelet | Mesh bracelet | Stainless steel bracelet |
| Power reserve | 41 hours | — | — |
| This watch | Closely matched | Closely matched |
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 comparedHow long does it run for when it's not worn?
About 41 hours fully wound — enough to survive a night off the wrist, but not a full weekend.
Will it fit my wrist?
Lug-to-lug is 46mm, which suits wrists from roughly 16cm (6¼ 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
F.Hinds at £280 is the cheapest of 3 UK retailers, against £290 at the dearest — a difference of £10.
Has the price changed recently?
It's currently at its lowest recorded price since we began tracking it. It's ranged between £280 and £290, today it's £280.
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