Seiko Cal. 5660 - 640

The 5660-640 is a sought-after Hand-Winding piece from Seiko's golden era. Powered by the 5660 caliber with 35j jewels beating at 28,800 bph, it delivers a 58 hours power reserve. [seikata-wm-690216fa8daa]

Also known as: Helmet, Silverwave

Specifications

Movement

Hand-Winding

Case Material

Gold-Plated

Case Width

39mm

Case Thickness

9.0mm

Lug Width

19mm

Crystal

Sapphire

Bezel

Fixed

Water Resistance

130m

Dial Color

Black

Jewels

35j

Frequency

28,800 bph

Power Reserve

58 hours

Year

1976

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