Seiko Cal. 5631 - 150

This Spring Drive model from 1991 features a 41mm Hardlex-Coated Steel case. The Inner Rotating bezel and 41mm case give it a distinctive presence on the wrist. [seikata-wm-997a114d11af]

Also known as: Sumo, Sportsmatic

Specifications

Movement

Spring Drive

Case Material

Hardlex-Coated Steel

Case Width

41mm

Case Thickness

14.0mm

Lug Width

21mm

Crystal

Mineral

Bezel

Inner Rotating

Water Resistance

190m

Dial Color

Black

Jewels

18j

Frequency

28,800 bph

Power Reserve

43 hours

Year

1991

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