Seiko Cal. 6640 - 398

Released in 1983, the Cal. 6640 with design code 398 was part of Seiko's domestic market collection. It features a Blue Sunburst dial protected by a Acrylic crystal and offers 110m of water resistance. [seikata-wm-ba8cf8495ed8]

Also known as: Monster, Goldfeather

Specifications

Movement

Automatic

Case Material

Stainless Steel

Case Width

35mm

Case Thickness

10.6mm

Lug Width

20mm

Crystal

Acrylic

Bezel

Fixed

Water Resistance

110m

Dial Color

Blue Sunburst

Jewels

32j

Frequency

21,600 bph

Power Reserve

49 hours

Year

1983

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