Seiko Cal. 3881 - 637

The Seiko 3881-637 represents an important milestone in Seiko's 1971 lineup. The Inner Rotating bezel and 43mm case give it a distinctive presence on the wrist. [seikata-wm-1c52ddbf369c]

Also known as: Sportsmatic

Specifications

Movement

Spring Drive

Case Material

Gold-Plated

Case Width

43mm

Case Thickness

9.9mm

Lug Width

19mm

Crystal

Hardlex

Bezel

Inner Rotating

Water Resistance

120m

Dial Color

Navy

Jewels

23j

Frequency

21,600 bph

Power Reserve

65 hours

Year

1971

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