Seiko Cal. 5631 - 540

The Seiko 5631-540 represents an important milestone in Seiko's 1966 lineup. The Inner Rotating bezel and 35mm case give it a distinctive presence on the wrist. [seikata-wm-8c348b93dffa]

Also known as: Panda, Helmet

Specifications

Movement

Solar

Case Material

Two-Tone

Case Width

35mm

Case Thickness

9.0mm

Lug Width

21mm

Crystal

Hardlex

Bezel

Inner Rotating

Water Resistance

130m

Dial Color

Black

Jewels

29j

Frequency

28,800 bph

Power Reserve

46 hours

Year

1966

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