Seiko Cal. 5640 - 721

The Seiko 5640-721 represents an important milestone in Seiko's 1981 lineup. It features a Green dial protected by a Hardlex crystal and offers 30m of water resistance. [seikata-wm-e2e36e428c36]

Also known as: Rally, Arnie

Specifications

Movement

Hand-Winding

Case Material

Two-Tone

Case Width

36mm

Case Thickness

15.7mm

Lug Width

19mm

Crystal

Hardlex

Bezel

Bidirectional

Water Resistance

30m

Dial Color

Green

Jewels

23j

Frequency

21,600 bph

Power Reserve

40 hours

Year

1981

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