Seiko Cal. 6631 - 206

This Spring Drive model from 1972 features a 44mm Stainless Steel case. Powered by the 6631 caliber with 31j jewels beating at 36,000 bph, it delivers a 68 hours power reserve. [seikata-wm-d1199ca1b0c5]

Also known as: Bullhead, Arnie

Specifications

Movement

Spring Drive

Case Material

Stainless Steel

Case Width

44mm

Case Thickness

12.7mm

Lug Width

21mm

Crystal

Mineral

Bezel

Inner Rotating

Water Resistance

100m

Dial Color

Silver

Jewels

31j

Frequency

36,000 bph

Power Reserve

68 hours

Year

1972

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