Seiko Cal. 5638 - 940

The Seiko 5638-940 represents an important milestone in Seiko's 1971 lineup. Powered by the 5638 caliber with 35j jewels beating at 28,800 bph, it delivers a 63 hours power reserve. [seikata-wm-9670f1ea29ba]

Also known as: Bullhead, Helmet

Specifications

Movement

Hand-Winding

Case Material

Gold-Plated

Case Width

44mm

Case Thickness

12.6mm

Lug Width

20mm

Crystal

Mineral

Bezel

Rotating

Water Resistance

160m

Dial Color

Blue Sunburst

Jewels

35j

Frequency

28,800 bph

Power Reserve

63 hours

Year

1971

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