Seiko Cal. 6637 - 312

The Seiko 6637-312 represents an important milestone in Seiko's 1987 lineup. Powered by the 6637 caliber with 31j jewels beating at 21,600 bph, it delivers a 38 hours power reserve. [seikata-wm-5efde95de14c]

Also known as: UFO, Baby Tuna

Specifications

Movement

Spring Drive

Case Material

Hardlex-Coated Steel

Case Width

44mm

Case Thickness

9.0mm

Lug Width

18mm

Crystal

Sapphire

Bezel

Bidirectional

Water Resistance

60m

Dial Color

Cream

Jewels

31j

Frequency

21,600 bph

Power Reserve

38 hours

Year

1987

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