SEIKO 5 SPORTS HDB004K1 SKX AUTOMATIC MEN WATCH
HDB004K1
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- Warranty 3 Years
The Seiko 5 Sports HDB004 belongs to the SKX Series — the part of the 5 Sports line built on Seiko's long-running sports case, with a unidirectional rotating bezel, crown guards integrated into the case flank, and a stainless steel bracelet. It is a 2026 release, and it sits at the substantial end of the range: 42.5mm across, 14.2mm thick and 169 grams complete.
The movement is Calibre 4R36 — automatic, wound by the motion of your wrist, with 24 jewels, manual winding, a stop second hand function and approximately 41 hours of power reserve. Day and date are both on the dial. The crystal is curved Hardlex, the case back is see-through so the movement stays visible, and the watch is rated to 100 metres. The bracelet fastens on a one-push three-fold clasp with a double-lock.
At a Glance
- BrandSeiko
- Collection5 Sports, SKX Series
- MovementCalibre 4R36 Automatic
- Case Size42.5mm
- Case Thickness14.2mm
- Lug-to-Lug46.0mm
- BezelUnidirectional Rotating
- GlassCurved Hardlex
- Functions3 Hands + Day & Date
- Water Resistance100m (10 BAR)
- BraceletStainless Steel, 22mm
- Weight169g
Why You'll Love It
- No battery. Calibre 4R36 winds itself from the motion of your wrist, and you can wind it by hand when it has been sitting. Worn regularly, it simply keeps running.
- 46.0mm lug-to-lug on a 42.5mm case. That span is short for the diameter, which is why the SKX case shape sits within the wrist instead of hanging over the edges.
- The unidirectional bezel is a working tool. Line the marker up with the minute hand and you have elapsed time at a glance — for parking, cooking, laps, anything timed.
- 169 grams of steel on the wrist. This is a watch you feel, and for a lot of buyers that solidity is exactly the point.
- Stop second hand function and hand winding. You can set it to the second against a reference, and wind it from cold without shaking it.
- The see-through case back leaves the movement visible — the balance wheel running, the rotor turning as you move.
- Day and date both on the dial, which is the complication you notice the absence of within a week of living without it.
- 100 metres of water resistance, so rain and swimming are not a consideration.
Perfect For
- First Automatic Watch
- Everyday Wear
- Larger Wrists
- Outdoors & Travel
- Weekend & Casual
- Mechanical Watch Collectors
- Students & Graduates
- Gift for Him
Key Features
- Calibre 4R36 automatic movement — 24 jewels and approximately 41 hours of power reserve, self-winding from wrist motion with manual winding available.
- Stop second hand function — pulling the crown halts the seconds hand so the time can be set precisely against a reference.
- Day and date display — both indications on the dial, set from the crown.
- Unidirectional rotating bezel — turns one way only, so an accidental knock can only ever shorten the elapsed time you have measured, never lengthen it.
- Curved Hardlex crystal — Seiko's own hardened mineral glass, shaped to follow the profile of the case.
- See-through and screw case back — a display window onto the movement, in a screw-down case back that maintains the water resistance rating.
- LumiBrite on hands and indexes — Seiko's luminous compound charges under light and reads clearly in the dark without drawing any power.
- Stainless steel case and bracelet — 42.5mm across, 14.2mm thick and 46.0mm lug-to-lug, at a total weight of 169 grams.
- One-push three-fold clasp with double-lock — a folding clasp with a secondary catch, on a 22mm lug width.
- 100-metre water resistance and magnetic resistance of 4,800 A/m.
Technical Specifications
The Seiko 5 Sports HDB004 is a 42.5mm automatic watch from the SKX Series, powered by Calibre 4R36 with 24 jewels and approximately 41 hours of power reserve. The stainless steel case measures 14.2mm thick and 46.0mm lug-to-lug at a total weight of 169 grams, with a unidirectional rotating bezel, a curved Hardlex crystal and a see-through screw case back. It features LumiBrite on the hands and indexes, a day and date display, hand winding and a stop second hand function, a stainless steel bracelet on a 22mm lug width with a one-push three-fold clasp and double-lock, magnetic resistance of 4,800 A/m, and 100-metre water resistance.
| Model Number | HDB004 |
| Series | 5 Sports, SKX Series |
| Case Material | Stainless Steel |
| Case Diameter | 42.5mm |
| Case Thickness | 14.2mm |
| Lug-to-Lug | 46.0mm |
| Lug Width | 22mm |
| Weight | 169g |
| Bezel | Unidirectional Rotating |
| Glass | Curved Hardlex |
| Caseback | See-Through, Screw Case Back |
| Water Resistance | 100 Metres (10 BAR) |
| Magnetic Resistance | 4,800 A/m |
| LumiBrite | Hands & Indexes |
| Hand Indicators | Hour, Minute, Seconds |
| Calendar | Day of the Week + Date |
| Material | Stainless Steel |
| Lug Width | 22mm |
| Clasp | One-Push Three-Fold with Double-Lock |
| Calibre | Seiko 4R36 |
| Type | Automatic with Manual Winding |
| Jewels | 24 |
| Power Reserve | Approx. 41 Hours |
| Hand Winding | Yes |
| Stop Second Hand | Yes |
| Function | 3 Hands + Day & Date |
Best Matched With
- Field Jacket
- White Oxford Shirt
- Grey Crewneck
- Dark Denim
- Charcoal Chinos
- Technical Outerwear
- Leather Sneakers
Frequently Asked Questions
How does an automatic watch work — do I need to charge it?
No charging and no battery. A weighted rotor inside Calibre 4R36 spins as your wrist moves, winding the mainspring. Wearing it through a normal day keeps it running. If it stops after sitting unworn, wind it by hand — roughly 30 to 40 turns of the crown — and it will start again.
What happens if I do not wear it for a few days?
It stops. The power reserve is approximately 41 hours from a full wind, so a watch taken off on Friday evening will typically have stopped by Sunday. Wind it by hand, reset the time, day and date, and carry on. This is normal for every mechanical watch and does not harm it.
What is the stop second hand function for?
Pulling the crown out to the time-setting position halts the seconds hand. That lets you line the watch up to the second against a reference before pushing the crown back in, instead of getting the minutes right and the seconds approximately right.
What is the rotating bezel for?
Measuring elapsed time. Turn the bezel until its zero marker lines up with the minute hand, and from then on the minute hand reads how long has passed directly off the bezel scale. It turns in one direction only, which is a safety feature: if it gets knocked, it can only ever make the elapsed time read longer than it really is, never shorter.
Is this a diver's watch?
No, and the distinction matters. The case shape and rotating bezel come from Seiko's sports watch heritage, but this model is rated to 100 metres and is not certified as a diver's watch. It is fine for swimming, snorkelling and recreational water activity. For scuba diving you need a watch specified and marked as a diver's watch — the Prospex line is where those sit.
How does 42.5mm wear?
More comfortably than the number suggests, in footprint at least. The lug-to-lug measurement is 46.0mm, which is genuinely short for a 42.5mm case, so it sits within the wrist rather than hanging over the edges. What you will notice is the weight and height — 169 grams and 14.2mm thick make this a substantial watch. Try it on at any City Chain outlet if you are between sizes.
Can I swim with it?
Yes. At 100-metre water resistance it handles swimming and recreational water activity. Never operate the crown while the watch is wet, and make sure the crown is fully pushed in before it goes near water. Rinse with fresh water after the sea or a chlorinated pool.
How do I set the day and date?
Both are set from the crown's intermediate position, with the seconds hand still running. Avoid adjusting the date between roughly 9pm and 3am, when the movement's calendar mechanism is engaged and changing it can cause damage. Set the time forward past noon first if you need to confirm you are in the afternoon rather than the small hours.
Is the bracelet adjustable?
Yes. Links can be added or removed to size it, and the one-push three-fold clasp has a double-lock — a secondary catch that holds the clasp shut if the main one is knocked open. City Chain offers complimentary bracelet sizing at any outlet; bring your warranty book along for the service.
Does a mechanical watch need servicing?
Yes, eventually. A mechanical movement runs on lubricated moving parts that wear over years of use, so a service every few years keeps it running to specification. City Chain can arrange servicing through Seiko's authorised service network — bring your warranty book. Browse the full Seiko 5 collection.
What warranty does this watch come with?
The HDB004 comes with a 3-year warranty when purchased from City Chain Singapore, an authorised Seiko retailer. Keep your warranty card and proof of purchase — both are required when submitting the watch for service.
Why Buy from City Chain Singapore
- Authorised Retailer 100% genuine Seiko product
- 3-Year Warranty Covered on every purchase
- Free Shipping All orders within Singapore
- Bracelet Adjustment Size it in-store
Extra $10 OFF with min. $80 spend
Use Code: STYLE10
Extra $15 OFF with min. $210 spend
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Extra $25 OFF with min. $310 spend
Use Code: STYLE25
Caliber Number: 4R36
Movement Type: Automatic with manual winding
Power reserve: Approx. 41 hours
Jewels: 24
Stop second hand function
Day/Date display
Case Material: Stainless steel
Case Thickness: 14.2mm
Case Diameter: 42.5mm
Lug-to-lug: 46.0mm
Crystal: Curved Hardlex
Lumibrite on hands and index(es)
Three-fold clasp with push button release
Distance between lugs: 22mm
Water Resistance: 10 bar
Magnetic Resistance: 4,800 A/m
Weight: 169.0g
Unidirectional rotating bezel
Three-fold clasp with secure lock
See-through & Screw case back
Delivery within Singapore | Order by 11AM
(Checkout options may vary depending on minimum order requirements)
• Free Standard Delivery (3 business days)
• Free Next Day Delivery
• Express Delivery at $30 (order by 2PM)
• Click & Collect (ready in 2–3 business days)
Weekend & Public Holiday Orders
Orders placed during this time will be processed on the next business day.
For online purchase, you can have bracelet or leather strap adjustments done at any City Chain store. Please bring along your warranty book for the service.
