Seiko Cal. 5640 - 831

Seiko 5640-831

The 5640-831 is a sought-after Kinetic piece from Seiko's golden era. Powered by the 5640 caliber with 28j jewels beating at 21,600 bph, it delivers a 59 hours power reserve. [seikata-wm-5189441a0c8b]

Also known as: Sportsmatic

Specifications

Movement
Kinetic
Case Material
Stainless Steel
Case Width
35mm
Case Thickness
13.0mm
Lug Width
20mm
Crystal
Hardlex
Bezel
Rotating
Water Resistance
90m
Dial Color
Green
Jewels
28j
Frequency
21,600 bph
Power Reserve
59 hours
Year
1991

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seikata-wm-5189441a0c8b