Seiko Cal. 6631 - 897

This Spring Drive model from 1977 features a 38mm Titanium case. With its 20mm lug width and 15.6mm profile, it sits comfortably on most wrists. [seikata-wm-a2182628b61e]

Also known as: Sumo, Sportsmatic

Specifications

Movement

Spring Drive

Case Material

Titanium

Case Width

38mm

Case Thickness

15.6mm

Lug Width

20mm

Crystal

Sapphire

Bezel

Bidirectional

Water Resistance

120m

Dial Color

Green

Jewels

29j

Frequency

21,600 bph

Power Reserve

54 hours

Year

1977

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