Seiko Cal. 5639 - 366

The Seiko 5639-366 represents an important milestone in Seiko's 1966 lineup. Powered by the 5639 caliber with 22j jewels beating at 21,600 bph, it delivers a 64 hours power reserve. [seikata-wm-e51de13b28a2]

Also known as: Baby Tuna

Specifications

Movement

Automatic

Case Material

Hardlex-Coated Steel

Case Width

38mm

Case Thickness

9.4mm

Lug Width

18mm

Crystal

Sapphire

Bezel

Inner Rotating

Water Resistance

60m

Dial Color

White

Jewels

22j

Frequency

21,600 bph

Power Reserve

64 hours

Year

1966

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