Seiko Cal. 6638 - 931

The Seiko 6638-931 represents an important milestone in Seiko's 1973 lineup. The Fixed bezel and 34mm case give it a distinctive presence on the wrist. [seikata-wm-62f3616396c7]

Also known as: Sumo

Specifications

Movement

Hand-Winding

Case Material

PVD Black

Case Width

34mm

Case Thickness

10.5mm

Lug Width

20mm

Crystal

Hardlex

Bezel

Fixed

Water Resistance

80m

Dial Color

Cream

Jewels

17j

Frequency

36,000 bph

Power Reserve

39 hours

Year

1973

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