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Round stainless steel automatic watch with black dial and metal bracelet

Seiko

Seiko 5 Sports SRPJ81K1 Automatic Watch 36.40 mm 100m

SKU CH-8PXJ-2HNAH

Automatic sports watch with a 36.40 mm stainless steel case, black dial, day-date display and 100 m water resistance

  • Watch movementAutomatic
  • Product shapeRound
  • Watch face colorBlack
  • Dial markingsNumbers
  • Display typeAnalog
  • Date displayDate
  • Automatic 4R36 movement with 24 jewels powers the watch
  • 100 m water resistance suits swimming and snorkelling
  • Curved Hardlex crystal protects the black dial
  • Stainless steel case and bracelet resist daily wear
  • Day and date display adds practical convenience

Seiko 5 Sports 36.40 mm Automatic Watch

The Seiko 5 Sports SRPJ81K1 is a 36.40 mm stainless steel wristwatch driven by the automatic 4R36 calibre with 24 jewels. A black dial with applied numbers and a day-date window sits beneath a curved Hardlex crystal. The matching stainless steel bracelet secures with a deployment clasp for a firm fit. Water resistance is rated to 100 metres.

Suits daily wear and light aquatic activity

Buyers who want a compact automatic watch with a steel bracelet and 100 metre water resistance will find the 36.40 mm case comfortable for all-day use. The Hardlex crystal and deployment clasp add practical durability for office or weekend settings. Those needing a larger case diameter, a screw-down crown, or ISO dive certification should consider other models.

Caliber 4R36 with 24 jewels decides fit

The 4R36 automatic movement provides hand-winding and hacking seconds without a battery. Its 24-jewel construction supports reliable timekeeping for everyday wear. If the buyer requires a movement with a longer power reserve, higher beat rate, or chronometer certification, this calibre will not meet that requirement.

How it compares

Measured against everything we stock in Analog & Digital Wristwatches, at today’s prices. Recalculated every night.

Price $219.99
Pricier than about 75% of the 2,679 comparable items (median $130.99).

Specifications

Product
Brand nameSeiko
Design styleSports
Watch face colorBlack
Item conditionNew
Display
Display typeAnalog
Size & build
Main materialStainless Steel
Product shapeRound
Strap materialStainless Steel
Closure typeDeployment Clasp
Bezel typeFixed Bezel
Case constructionPull Out Crown
Housing materialStainless Steel
Case size36.4 mm
Watch glassHardlex Crystal
Environment & compliance
Water resistance100m
More details
Watch movementAutomatic
Dial markingsNumbers
Date displayDate
Suitable forMale

Questions about this item

Will the 36.40 mm case and stainless-steel bracelet sit comfortably alongside my older 36 mm Seiko 5 on the same wrist?

The 36.40 mm case is only fractionally wider than a classic 36 mm case, and the matching stainless-steel bracelet with deployment clasp shares the same lug width, so both watches wear very similarly on the same wrist.

How can I verify the Caliber 4R36 automatic movement is running correctly after I set it up?

Wind the pull-out crown until you feel resistance, set the time and day-date, then confirm the seconds hand moves in a smooth sweep and the day-date window advances cleanly at midnight.

Does the box include the curved Hardlex crystal and 100 m water resistance, or must I purchase any protection separately?

The watch ships with the curved Hardlex crystal already fitted and is rated to 100 m water resistance; no extra crystal or seal kit is required.

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