Seiko Cal. 6640 - 563

The Seiko 6640-563 represents an important milestone in Seiko's 1978 lineup. With its 20mm lug width and 15.8mm profile, it sits comfortably on most wrists. [seikata-wm-b5c6047c5fa5]

Also known as: Bullhead, Sea Horse

Specifications

Movement

Automatic

Case Material

Two-Tone

Case Width

38mm

Case Thickness

15.8mm

Lug Width

20mm

Crystal

Mineral

Bezel

Bidirectional

Water Resistance

140m

Dial Color

Navy

Jewels

25j

Frequency

36,000 bph

Power Reserve

71 hours

Year

1978

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