Seiko Cal. 6640 - 638

The Seiko 6640-638 represents an important milestone in Seiko's 1999 lineup. With its 20mm lug width and 9.1mm profile, it sits comfortably on most wrists. [seikata-wm-32aa12fb2c0f]

Also known as: Sumo

Specifications

Movement

Spring Drive

Case Material

PVD Black

Case Width

36mm

Case Thickness

9.1mm

Lug Width

20mm

Crystal

Hardlex

Bezel

Bidirectional

Water Resistance

60m

Dial Color

Black

Jewels

18j

Frequency

36,000 bph

Power Reserve

50 hours

Year

1999

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