Seiko Cal. 6640 - 596

Released in 1965, the Cal. 6640 with design code 596 was part of Seiko's domestic market collection. Powered by the 6640 caliber with 25j jewels beating at 36,000 bph, it delivers a 58 hours power reserve. [seikata-wm-5c8ec0fe6b1d]

Also known as: Sumo, Emperor

Specifications

Movement

Spring Drive

Case Material

Gold-Plated

Case Width

43mm

Case Thickness

13.7mm

Lug Width

18mm

Crystal

Sapphire

Bezel

Rotating

Water Resistance

190m

Dial Color

Blue Sunburst

Jewels

25j

Frequency

36,000 bph

Power Reserve

58 hours

Year

1965

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