Seiko Cal. 6631 - 129

The 6631-129 is a sought-after Spring Drive piece from Seiko's golden era. Powered by the 6631 caliber with 31j jewels beating at 21,600 bph, it delivers a 48 hours power reserve. [seikata-wm-7684eae975f6]

Also known as: Monster, Sportsmatic

Specifications

Movement

Spring Drive

Case Material

Gold-Plated

Case Width

45mm

Case Thickness

10.5mm

Lug Width

22mm

Crystal

Mineral

Bezel

Rotating

Water Resistance

200m

Dial Color

Burgundy

Jewels

31j

Frequency

21,600 bph

Power Reserve

48 hours

Year

1979

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