Seiko Cal. 6640 - 961

The Seiko 6640-961 represents an important milestone in Seiko's 1968 lineup. Powered by the 6640 caliber with 31j jewels beating at 36,000 bph, it delivers a 61 hours power reserve. [seikata-wm-3c5f09222325]

Also known as: World Timer

Specifications

Movement

Quartz

Case Material

PVD Black

Case Width

38mm

Case Thickness

13.3mm

Lug Width

21mm

Crystal

Sapphire

Bezel

Fixed

Water Resistance

150m

Dial Color

Navy

Jewels

31j

Frequency

36,000 bph

Power Reserve

61 hours

Year

1968

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