Seiko Cal. 5640 - 638

The Seiko 5640-638 represents an important milestone in Seiko's 1968 lineup. Powered by the 5640 caliber with 26j jewels beating at 28,800 bph, it delivers a 38 hours power reserve. [seikata-wm-efef72c2cc1c]

Also known as: Turtle

Specifications

Movement

Hand-Winding

Case Material

Gold-Plated

Case Width

36mm

Case Thickness

11.6mm

Lug Width

22mm

Crystal

Sapphire

Bezel

Coin-Edge

Water Resistance

50m

Dial Color

Navy

Jewels

26j

Frequency

28,800 bph

Power Reserve

38 hours

Year

1968

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