Seiko Cal. 6636 - 639

The Seiko 6636-639 represents an important milestone in Seiko's 1971 lineup. Powered by the 6636 caliber with 18j jewels beating at 36,000 bph, it delivers a 48 hours power reserve. [seikata-wm-db800d456642]

Also known as: Helmet

Specifications

Movement

Spring Drive

Case Material

Gold-Plated

Case Width

37mm

Case Thickness

9.3mm

Lug Width

18mm

Crystal

Mineral

Bezel

Bidirectional

Water Resistance

100m

Dial Color

White

Jewels

18j

Frequency

36,000 bph

Power Reserve

48 hours

Year

1971

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