Seiko Cal. 5640 - 180

The Seiko 5640-180 represents an important milestone in Seiko's 1972 lineup. It features a Navy dial protected by a Acrylic crystal and offers 100m of water resistance. [seikata-wm-be686f0461a4]

Also known as: Baby Tuna, Flighty

Specifications

Movement

Hand-Winding

Case Material

Hardlex-Coated Steel

Case Width

40mm

Case Thickness

9.8mm

Lug Width

18mm

Crystal

Acrylic

Bezel

Fixed

Water Resistance

100m

Dial Color

Navy

Jewels

28j

Frequency

21,600 bph

Power Reserve

66 hours

Year

1972

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