Seiko Cal. 6631 - 861

This Spring Drive model from 1976 features a 45mm Titanium case. With its 20mm lug width and 9.1mm profile, it sits comfortably on most wrists. [seikata-wm-d7789e2f6eb4]

Also known as: Bullhead, Navigator

Specifications

Movement

Spring Drive

Case Material

Titanium

Case Width

45mm

Case Thickness

9.1mm

Lug Width

20mm

Crystal

Hardlex

Bezel

Fixed

Water Resistance

30m

Dial Color

Burgundy

Jewels

26j

Frequency

21,600 bph

Power Reserve

37 hours

Year

1976

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