Seiko Cal. 6640 - 542

The Seiko 6640-542 represents an important milestone in Seiko's 1967 lineup. It features a Green dial protected by a Acrylic crystal and offers 180m of water resistance. [seikata-wm-3ab7c70285c2]

Also known as: Sumo, Shogun

Specifications

Movement

Automatic

Case Material

Titanium

Case Width

44mm

Case Thickness

10.6mm

Lug Width

18mm

Crystal

Acrylic

Bezel

Bidirectional

Water Resistance

180m

Dial Color

Green

Jewels

34j

Frequency

36,000 bph

Power Reserve

46 hours

Year

1967

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