Seiko Cal. 6639 - 931

The Seiko 6639-931 represents an important milestone in Seiko's 1968 lineup. Powered by the 6639 caliber with 17j jewels beating at 28,800 bph, it delivers a 64 hours power reserve. [seikata-wm-e61670ea7b91]

Also known as: Shogun, Tuna

Specifications

Movement

Automatic

Case Material

Gold-Plated

Case Width

38mm

Case Thickness

12.9mm

Lug Width

22mm

Crystal

Sapphire

Bezel

Inner Rotating

Water Resistance

80m

Dial Color

Black

Jewels

17j

Frequency

28,800 bph

Power Reserve

64 hours

Year

1968

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