Seiko Cal. 6640 - 903

The Seiko 6640-903 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 44 hours power reserve. [seikata-wm-d220539ba836]

Also known as: Baby Tuna

Specifications

Movement

Automatic

Case Material

Stainless Steel

Case Width

36mm

Case Thickness

10.1mm

Lug Width

19mm

Crystal

Sapphire

Bezel

Coin-Edge

Water Resistance

30m

Dial Color

Black

Jewels

21j

Frequency

21,600 bph

Power Reserve

44 hours

Year

1973

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