Seiko Cal. 6631 - 764

This Spring Drive model from 1968 features a 34mm Stainless Steel case. Powered by the 6631 caliber with 35j jewels beating at 21,600 bph, it delivers a 51 hours power reserve. [seikata-wm-668dff50c969]

Also known as: Sportsmatic

Specifications

Movement

Spring Drive

Case Material

Stainless Steel

Case Width

34mm

Case Thickness

14.9mm

Lug Width

18mm

Crystal

Sapphire

Bezel

Coin-Edge

Water Resistance

70m

Dial Color

Burgundy

Jewels

35j

Frequency

21,600 bph

Power Reserve

51 hours

Year

1968

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