Seiko Cal. 5640 - 978

The Seiko 5640-978 represents an important milestone in Seiko's 1970 lineup. The Coin-Edge bezel and 43mm case give it a distinctive presence on the wrist. [seikata-wm-ca756fae5e73]

Specifications

Movement

Automatic

Case Material

Hardlex-Coated Steel

Case Width

43mm

Case Thickness

14.1mm

Lug Width

21mm

Crystal

Sapphire

Bezel

Coin-Edge

Water Resistance

100m

Dial Color

White

Jewels

35j

Frequency

28,800 bph

Power Reserve

71 hours

Year

1970

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