Seiko Cal. 5631 - 540

This Spring Drive model from 1973 features a 40mm Gold-Plated case. It features a Black dial protected by a Sapphire crystal and offers 180m of water resistance. [seikata-wm-f6b9a5887679]

Also known as: Silverwave, Bellmatic

Specifications

Movement

Spring Drive

Case Material

Gold-Plated

Case Width

40mm

Case Thickness

13.4mm

Lug Width

20mm

Crystal

Sapphire

Bezel

Fixed

Water Resistance

180m

Dial Color

Black

Jewels

36j

Frequency

21,600 bph

Power Reserve

64 hours

Year

1973

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