Seiko Cal. 6640 - 770

The Seiko 6640-770 represents an important milestone in Seiko's 1984 lineup. Powered by the 6640 caliber with 29j jewels beating at 21,600 bph, it delivers a 64 hours power reserve. [seikata-wm-f062c974b1e9]

Also known as: Bullhead, Silverwave

Specifications

Movement

Solar

Case Material

PVD Black

Case Width

39mm

Case Thickness

10.6mm

Lug Width

20mm

Crystal

Sapphire

Bezel

Rotating

Water Resistance

160m

Dial Color

Champagne

Jewels

29j

Frequency

21,600 bph

Power Reserve

64 hours

Year

1984

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