Seiko Cal. 6640 - 783

The 6640-783 is a sought-after Hand-Winding piece from Seiko's golden era. Powered by the 6640 caliber with 26j jewels beating at 36,000 bph, it delivers a 36 hours power reserve. [seikata-wm-bd91ec98e465]

Also known as: Sumo, Pogue

Specifications

Movement

Hand-Winding

Case Material

Hardlex-Coated Steel

Case Width

43mm

Case Thickness

15.7mm

Lug Width

20mm

Crystal

Hardlex

Bezel

Coin-Edge

Water Resistance

100m

Dial Color

White

Jewels

26j

Frequency

36,000 bph

Power Reserve

36 hours

Year

1978

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