Seiko Cal. 6631 - 187

The Seiko 6631-187 represents an important milestone in Seiko's 1997 lineup. With its 21mm lug width and 12.6mm profile, it sits comfortably on most wrists. [seikata-wm-2d5c2b23f6d0]

Also known as: Sumo

Specifications

Movement

Spring Drive

Case Material

Titanium

Case Width

42mm

Case Thickness

12.6mm

Lug Width

21mm

Crystal

Hardlex

Bezel

Coin-Edge

Water Resistance

200m

Dial Color

Black

Jewels

20j

Frequency

28,800 bph

Power Reserve

37 hours

Year

1997

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