Seiko Cal. 6647 - 721

Released in 1974, the Cal. 6647 with design code 721 was part of Seiko's domestic market collection. The Fixed bezel and 42mm case give it a distinctive presence on the wrist. [seikata-wm-a5da8290ca97]

Also known as: Helmet

Specifications

Movement

Spring Drive

Case Material

Stainless Steel

Case Width

42mm

Case Thickness

11.5mm

Lug Width

18mm

Crystal

Hardlex

Bezel

Fixed

Water Resistance

100m

Dial Color

Blue Sunburst

Jewels

19j

Frequency

21,600 bph

Power Reserve

37 hours

Year

1974

Related Models

• Seiko 6130-115
• Seiko 6195-641
• Seiko 7151-127
• Seiko 5244-861
• Seiko 6227-914
• Seiko 5246-950
• Seiko 7194-657
• Seiko 6237-980
• Seiko 5280-236
• Seiko 5292-666
• Seiko 6171-699
• Seiko 5289-653