Seiko Cal. 6637 - 718

The 6637-718 is a sought-after Spring Drive piece from Seiko's golden era. Powered by the 6637 caliber with 20j jewels beating at 36,000 bph, it delivers a 54 hours power reserve. [seikata-wm-5019eb8fcaf4]

Also known as: Shogun, Baby Tuna

Specifications

Movement

Spring Drive

Case Material

Stainless Steel

Case Width

42mm

Case Thickness

12.8mm

Lug Width

20mm

Crystal

Acrylic

Bezel

Rotating

Water Resistance

100m

Dial Color

Black

Jewels

20j

Frequency

36,000 bph

Power Reserve

54 hours

Year

1981

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