Seiko Cal. 6640 - 730

The Seiko 6640-730 represents an important milestone in Seiko's 1983 lineup. It features a Navy dial protected by a Acrylic crystal and offers 160m of water resistance. [seikata-wm-1245b5dd1440]

Also known as: Helmet, Sportsmatic

Specifications

Movement

Automatic

Case Material

Titanium

Case Width

39mm

Case Thickness

13.5mm

Lug Width

21mm

Crystal

Acrylic

Bezel

Fixed

Water Resistance

160m

Dial Color

Navy

Jewels

27j

Frequency

36,000 bph

Power Reserve

70 hours

Year

1983

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