Seiko Cal. 5631 - 188

This Hand-Winding model from 1973 features a 36mm Stainless Steel case. It features a Blue Sunburst dial protected by a Hardlex crystal and offers 40m of water resistance. [seikata-wm-81ac94cfa8fd]

Also known as: Bullhead, Bellmatic

Specifications

Movement

Hand-Winding

Case Material

Stainless Steel

Case Width

36mm

Case Thickness

8.4mm

Lug Width

21mm

Crystal

Hardlex

Bezel

Fixed

Water Resistance

40m

Dial Color

Blue Sunburst

Jewels

22j

Frequency

28,800 bph

Power Reserve

36 hours

Year

1973

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