Seiko Cal. 5640 - 975

The Seiko 5640-975 represents an important milestone in Seiko's 1968 lineup. It features a Navy dial protected by a Acrylic crystal and offers 40m of water resistance. [seikata-wm-670d6ba90f23]

Also known as: Helmet, Flighty

Specifications

Movement

Automatic

Case Material

PVD Black

Case Width

37mm

Case Thickness

14.5mm

Lug Width

18mm

Crystal

Acrylic

Bezel

Inner Rotating

Water Resistance

40m

Dial Color

Navy

Jewels

22j

Frequency

36,000 bph

Power Reserve

37 hours

Year

1968

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