Seiko Cal. 6631 - 840

Seiko 6631-840

The 6631-840 is a sought-after Automatic piece from Seiko's golden era. With its 18mm lug width and 13.6mm profile, it sits comfortably on most wrists. [seikata-wm-92f5d16be252]

Also known as: Monster, Silverwave

Specifications

Movement
Automatic
Case Material
Hardlex-Coated Steel
Case Width
44mm
Case Thickness
13.6mm
Lug Width
18mm
Crystal
Acrylic
Bezel
Fixed
Water Resistance
80m
Dial Color
Blue Sunburst
Jewels
30j
Frequency
28,800 bph
Power Reserve
37 hours
Year
1974

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