Seiko Cal. 6640 - 837

The Seiko 6640-837 represents an important milestone in Seiko's 1966 lineup. Powered by the 6640 caliber with 29j jewels beating at 28,800 bph, it delivers a 54 hours power reserve. [seikata-wm-f5de6314d12d]

Also known as: Tuna, Panda

Specifications

Movement

Spring Drive

Case Material

Two-Tone

Case Width

43mm

Case Thickness

12.5mm

Lug Width

18mm

Crystal

Acrylic

Bezel

Rotating

Water Resistance

190m

Dial Color

Blue Sunburst

Jewels

29j

Frequency

28,800 bph

Power Reserve

54 hours

Year

1966

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