Seiko Cal. 6631 - 408

Seiko 6631-408

This Automatic model from 1971 features a 38mm Two-Tone case. Powered by the 6631 caliber with 31j jewels beating at 36,000 bph, it delivers a 61 hours power reserve. [seikata-wm-8902d9d744ba]

Also known as: Monster

Specifications

Movement
Automatic
Case Material
Two-Tone
Case Width
38mm
Case Thickness
9.1mm
Lug Width
20mm
Crystal
Acrylic
Bezel
Coin-Edge
Water Resistance
180m
Dial Color
White
Jewels
31j
Frequency
36,000 bph
Power Reserve
61 hours
Year
1971

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