Seiko Cal. 6647 - 821

The Seiko 6647-821 represents an important milestone in Seiko's 1972 lineup. With its 21mm lug width and 14.1mm profile, it sits comfortably on most wrists. [seikata-wm-558e62069195]

Also known as: Helmet, Rally

Specifications

Movement

Spring Drive

Case Material

Titanium

Case Width

41mm

Case Thickness

14.1mm

Lug Width

21mm

Crystal

Acrylic

Bezel

Bidirectional

Water Resistance

180m

Dial Color

Blue Sunburst

Jewels

32j

Frequency

21,600 bph

Power Reserve

61 hours

Year

1972

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