Seiko Cal. 5631 - 640

The 5631-640 is a sought-after Spring Drive piece from Seiko's golden era. The Fixed bezel and 37mm case give it a distinctive presence on the wrist. [seikata-wm-54f3fb5f184e]

Specifications

Movement

Spring Drive

Case Material

Gold-Plated

Case Width

37mm

Case Thickness

15.5mm

Lug Width

19mm

Crystal

Hardlex

Bezel

Fixed

Water Resistance

140m

Dial Color

White

Jewels

17j

Frequency

21,600 bph

Power Reserve

37 hours

Year

1986

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