Seiko Cal. 6631 - 437

The Seiko 6631-437 represents an important milestone in Seiko's 1969 lineup. It features a Navy dial protected by a Mineral crystal and offers 140m of water resistance. [seikata-wm-dea711d073c7]

Also known as: Bullhead, Goldfeather

Specifications

Movement

Spring Drive

Case Material

Hardlex-Coated Steel

Case Width

41mm

Case Thickness

14.1mm

Lug Width

21mm

Crystal

Mineral

Bezel

Inner Rotating

Water Resistance

140m

Dial Color

Navy

Jewels

27j

Frequency

28,800 bph

Power Reserve

45 hours

Year

1969

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