Seiko Cal. 6631 - 431

The Seiko 6631-431 represents an important milestone in Seiko's 1975 lineup. With its 18mm lug width and 12.6mm profile, it sits comfortably on most wrists. [seikata-wm-4186bb53f91f]

Also known as: Bullhead

Specifications

Movement

Automatic

Case Material

Gold-Plated

Case Width

44mm

Case Thickness

12.6mm

Lug Width

18mm

Crystal

Sapphire

Bezel

Fixed

Water Resistance

70m

Dial Color

Green

Jewels

17j

Frequency

28,800 bph

Power Reserve

57 hours

Year

1975

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