Seiko Cal. 6643 - 831

The 6643-831 is a sought-after Spring Drive piece from Seiko's golden era. Powered by the 6643 caliber with 19j jewels beating at 28,800 bph, it delivers a 50 hours power reserve. [seikata-wm-fb3db9be8a85]

Also known as: Monster, Tuna

Specifications

Movement

Spring Drive

Case Material

PVD Black

Case Width

39mm

Case Thickness

13.0mm

Lug Width

19mm

Crystal

Sapphire

Bezel

Rotating

Water Resistance

80m

Dial Color

Burgundy

Jewels

19j

Frequency

28,800 bph

Power Reserve

50 hours

Year

1970

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