Seiko Cal. 6638 - 645

This Spring Drive model from 1976 features a 43mm Titanium case. With its 21mm lug width and 13.9mm profile, it sits comfortably on most wrists. [seikata-wm-04342d576723]

Also known as: World Timer

Specifications

Movement

Spring Drive

Case Material

Titanium

Case Width

43mm

Case Thickness

13.9mm

Lug Width

21mm

Crystal

Acrylic

Bezel

Rotating

Water Resistance

170m

Dial Color

Navy

Jewels

20j

Frequency

21,600 bph

Power Reserve

39 hours

Year

1976

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