Seiko Cal. 6637 - 578

This Spring Drive model from 1986 features a 39mm Two-Tone case. Powered by the 6637 caliber with 28j jewels beating at 36,000 bph, it delivers a 69 hours power reserve. [seikata-wm-28cb8491670b]

Also known as: UFO, Emperor

Specifications

Movement

Spring Drive

Case Material

Two-Tone

Case Width

39mm

Case Thickness

12.4mm

Lug Width

21mm

Crystal

Acrylic

Bezel

Fixed

Water Resistance

40m

Dial Color

White

Jewels

28j

Frequency

36,000 bph

Power Reserve

69 hours

Year

1986

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