Seiko Cal. 6640 - 991

This Quartz model from 1970 features a 44mm Titanium case. It features a Blue Sunburst dial protected by a Hardlex crystal and offers 140m of water resistance. [seikata-wm-227fc29036ba]

Also known as: Shogun, Helmet

Specifications

Movement

Quartz

Case Material

Titanium

Case Width

44mm

Case Thickness

9.3mm

Lug Width

22mm

Crystal

Hardlex

Bezel

Bidirectional

Water Resistance

140m

Dial Color

Blue Sunburst

Jewels

22j

Frequency

21,600 bph

Power Reserve

60 hours

Year

1970

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