Seiko Cal. 5631 - 641

The Seiko 5631-641 represents an important milestone in Seiko's 1981 lineup. The Bidirectional bezel and 43mm case give it a distinctive presence on the wrist. [seikata-wm-8e1200b97d7c]

Also known as: Sea Horse, Golden Tuna

Specifications

Movement

Spring Drive

Case Material

Gold-Plated

Case Width

43mm

Case Thickness

11.5mm

Lug Width

22mm

Crystal

Hardlex

Bezel

Bidirectional

Water Resistance

100m

Dial Color

Burgundy

Jewels

27j

Frequency

36,000 bph

Power Reserve

66 hours

Year

1981

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