Seiko Cal. 6631 - 640

Seiko 6631-640

The 6631-640 is a sought-after Solar piece from Seiko's golden era. The Rotating bezel and 44mm case give it a distinctive presence on the wrist. [seikata-wm-de5459cf7651]

Also known as: Monster, Bullhead

Specifications

Movement
Solar
Case Material
Titanium
Case Width
44mm
Case Thickness
8.6mm
Lug Width
22mm
Crystal
Acrylic
Bezel
Rotating
Water Resistance
140m
Dial Color
Black
Jewels
26j
Frequency
21,600 bph
Power Reserve
68 hours
Year
1968

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