Seiko Cal. 5631 - 638

The Seiko 5631-638 represents an important milestone in Seiko's 1979 lineup. Powered by the 5631 caliber with 28j jewels beating at 36,000 bph, it delivers a 47 hours power reserve. [seikata-wm-aca66992f2d0]

Also known as: Sea Horse

Specifications

Movement

Kinetic

Case Material

Hardlex-Coated Steel

Case Width

36mm

Case Thickness

11.3mm

Lug Width

19mm

Crystal

Acrylic

Bezel

Coin-Edge

Water Resistance

90m

Dial Color

Burgundy

Jewels

28j

Frequency

36,000 bph

Power Reserve

47 hours

Year

1979

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