Seiko Cal. 6640 - 640

The Seiko 6640-640 represents an important milestone in Seiko's 1965 lineup. Powered by the 6640 caliber with 36j jewels beating at 36,000 bph, it delivers a 66 hours power reserve. [seikata-wm-c738287b9550]

Also known as: Helmet, Crown

Specifications

Movement

Hand-Winding

Case Material

Stainless Steel

Case Width

35mm

Case Thickness

11.3mm

Lug Width

18mm

Crystal

Mineral

Bezel

Fixed

Water Resistance

60m

Dial Color

Black

Jewels

36j

Frequency

36,000 bph

Power Reserve

66 hours

Year

1965

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