Seiko Cal. 5631 - 312

This Automatic model from 1987 features a 46mm Hardlex-Coated Steel case. With its 21mm lug width and 9.8mm profile, it sits comfortably on most wrists. [seikata-wm-f3cc6381ced9]

Also known as: Baby Tuna

Specifications

Movement

Automatic

Case Material

Hardlex-Coated Steel

Case Width

46mm

Case Thickness

9.8mm

Lug Width

21mm

Crystal

Sapphire

Bezel

Fixed

Water Resistance

90m

Dial Color

Black

Jewels

25j

Frequency

36,000 bph

Power Reserve

70 hours

Year

1987

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