Seiko Cal. 6640 - 820

The 6640-820 is a sought-after Hand-Winding piece from Seiko's golden era. Powered by the 6640 caliber with 29j jewels beating at 36,000 bph, it delivers a 69 hours power reserve. [seikata-wm-dacc24f41c45]

Also known as: Bullhead

Specifications

Movement

Hand-Winding

Case Material

Gold-Plated

Case Width

37mm

Case Thickness

15.0mm

Lug Width

21mm

Crystal

Sapphire

Bezel

Rotating

Water Resistance

100m

Dial Color

Champagne

Jewels

29j

Frequency

36,000 bph

Power Reserve

69 hours

Year

1965

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