Seiko Cal. 5631 - 686

This Spring Drive model from 1977 features a 35mm PVD Black case. Powered by the 5631 caliber with 31j jewels beating at 36,000 bph, it delivers a 69 hours power reserve. [seikata-wm-7e7022cbdcc5]

Also known as: UFO

Specifications

Movement

Spring Drive

Case Material

PVD Black

Case Width

35mm

Case Thickness

11.2mm

Lug Width

22mm

Crystal

Hardlex

Bezel

Bidirectional

Water Resistance

90m

Dial Color

Black

Jewels

31j

Frequency

36,000 bph

Power Reserve

69 hours

Year

1977

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