Seiko Cal. 6640 - 957

Seiko 6640-957

The 6640-957 is a sought-after Spring Drive piece from Seiko's golden era. Powered by the 6640 caliber with 27j jewels beating at 21,600 bph, it delivers a 40 hours power reserve. [seikata-wm-9b16b499a6ff]

Also known as: Turtle, Crown

Specifications

Movement
Spring Drive
Case Material
Gold-Plated
Case Width
39mm
Case Thickness
15.4mm
Lug Width
22mm
Crystal
Hardlex
Bezel
Bidirectional
Water Resistance
50m
Dial Color
Silver
Jewels
27j
Frequency
21,600 bph
Power Reserve
40 hours
Year
1983

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seikata-wm-9b16b499a6ff