Seiko Cal. 5631 - 660

The 5631-660 is a sought-after Hand-Winding piece from Seiko's golden era. Powered by the 5631 caliber with 26j jewels beating at 36,000 bph, it delivers a 71 hours power reserve. [seikata-wm-4ff7e32adf6c]

Also known as: Sportsmatic

Specifications

Movement

Hand-Winding

Case Material

Hardlex-Coated Steel

Case Width

38mm

Case Thickness

12.6mm

Lug Width

19mm

Crystal

Acrylic

Bezel

Bidirectional

Water Resistance

100m

Dial Color

Champagne

Jewels

26j

Frequency

36,000 bph

Power Reserve

71 hours

Year

1975

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