Seiko Cal. 5640 - 721

Seiko 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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