Seiko Cal. 5640 - 442

The 5640-442 is a sought-after Spring Drive piece from Seiko's golden era. Powered by the 5640 caliber with 34j jewels beating at 28,800 bph, it delivers a 55 hours power reserve. [seikata-wm-a1b44eb34e04]

Also known as: Helmet

Specifications

Movement

Spring Drive

Case Material

Stainless Steel

Case Width

46mm

Case Thickness

9.5mm

Lug Width

19mm

Crystal

Hardlex

Bezel

Fixed

Water Resistance

150m

Dial Color

Blue Sunburst

Jewels

34j

Frequency

28,800 bph

Power Reserve

55 hours

Year

1976

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