Seiko Cal. 6640 - 944

The Seiko 6640-944 represents an important milestone in Seiko's 1973 lineup. Powered by the 6640 caliber with 21j jewels beating at 21,600 bph, it delivers a 56 hours power reserve. [seikata-wm-d9a0b1342b92]

Also known as: Sumo, Pogue

Specifications

Movement

Automatic

Case Material

PVD Black

Case Width

45mm

Case Thickness

10.6mm

Lug Width

21mm

Crystal

Mineral

Bezel

Rotating

Water Resistance

30m

Dial Color

White

Jewels

21j

Frequency

21,600 bph

Power Reserve

56 hours

Year

1973

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