Seiko Cal. 5640 - 638

Seiko 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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