Seiko Cal. 6638 - 512

Seiko 6638-512

This Spring Drive model from 1971 features a 37mm Hardlex-Coated Steel case. With its 22mm lug width and 8.0mm profile, it sits comfortably on most wrists. [seikata-wm-8275cac6b4e8]

Also known as: Sumo, Helmet

Specifications

Movement
Spring Drive
Case Material
Hardlex-Coated Steel
Case Width
37mm
Case Thickness
8.0mm
Lug Width
22mm
Crystal
Hardlex
Bezel
Rotating
Water Resistance
80m
Dial Color
Silver
Jewels
33j
Frequency
21,600 bph
Power Reserve
66 hours
Year
1971

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