Seiko Cal. 5640 - 831

The Seiko 5640-831 represents an important milestone in Seiko's 1988 lineup. It features a Blue Sunburst dial protected by a Acrylic crystal and offers 140m of water resistance. [seikata-wm-4a6757f3f131]

Also known as: Panda, Helmet

Specifications

Movement

Spring Drive

Case Material

Gold-Plated

Case Width

35mm

Case Thickness

13.8mm

Lug Width

20mm

Crystal

Acrylic

Bezel

Bidirectional

Water Resistance

140m

Dial Color

Blue Sunburst

Jewels

25j

Frequency

28,800 bph

Power Reserve

63 hours

Year

1988

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