Seiko Cal. 6631 - 645

The 6631-645 is a sought-after Quartz piece from Seiko's golden era. Powered by the 6631 caliber with 31j jewels beating at 28,800 bph, it delivers a 71 hours power reserve. [seikata-wm-0e23376e8182]

Also known as: Sportsmatic

Specifications

Movement

Quartz

Case Material

Titanium

Case Width

37mm

Case Thickness

14.3mm

Lug Width

20mm

Crystal

Hardlex

Bezel

Inner Rotating

Water Resistance

120m

Dial Color

Champagne

Jewels

31j

Frequency

28,800 bph

Power Reserve

71 hours

Year

1997

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