Seiko Cal. 6640 - 397

The Seiko 6640-397 represents an important milestone in Seiko's 1980 lineup. It features a Navy dial protected by a Mineral crystal and offers 190m of water resistance. [seikata-wm-f271b9c4f5a3]

Also known as: Sea Horse

Specifications

Movement

Quartz

Case Material

Hardlex-Coated Steel

Case Width

43mm

Case Thickness

15.0mm

Lug Width

18mm

Crystal

Mineral

Bezel

Fixed

Water Resistance

190m

Dial Color

Navy

Jewels

23j

Frequency

21,600 bph

Power Reserve

67 hours

Year

1980

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