Seiko Cal. 5644 - 640

This Spring Drive model from 1973 features a 45mm PVD Black case. It features a Green dial protected by a Sapphire crystal and offers 40m of water resistance. [seikata-wm-308cd3b2aad4]

Specifications

Movement

Spring Drive

Case Material

PVD Black

Case Width

45mm

Case Thickness

14.8mm

Lug Width

18mm

Crystal

Sapphire

Bezel

Bidirectional

Water Resistance

40m

Dial Color

Green

Jewels

36j

Frequency

28,800 bph

Power Reserve

66 hours

Year

1973

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