Seiko Cal. 5631 - 402

The Seiko 5631-402 represents an important milestone in Seiko's 1968 lineup. Powered by the 5631 caliber with 24j jewels beating at 28,800 bph, it delivers a 64 hours power reserve. [seikata-wm-8ec52bcf003e]

Also known as: Tuna, Arnie

Specifications

Movement

Spring Drive

Case Material

Titanium

Case Width

36mm

Case Thickness

10.8mm

Lug Width

20mm

Crystal

Mineral

Bezel

Inner Rotating

Water Resistance

170m

Dial Color

Black

Jewels

24j

Frequency

28,800 bph

Power Reserve

64 hours

Year

1968

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