Seiko Cal. 5640 - 978

The Seiko 5640-978 represents an important milestone in Seiko's 1983 lineup. With its 18mm lug width and 15.3mm profile, it sits comfortably on most wrists. [seikata-wm-04cdb12f95a2]

Also known as: Sportsmatic

Specifications

Movement

Hand-Winding

Case Material

Two-Tone

Case Width

34mm

Case Thickness

15.3mm

Lug Width

18mm

Crystal

Acrylic

Bezel

Bidirectional

Water Resistance

150m

Dial Color

Burgundy

Jewels

26j

Frequency

21,600 bph

Power Reserve

37 hours

Year

1983

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