Seiko Cal. 6631 - 764

Seiko 6631-764

This Hand-Winding model from 1991 features a 37mm Two-Tone case. The Inner Rotating bezel and 37mm case give it a distinctive presence on the wrist. [seikata-wm-be1a97682438]

Also known as: Sumo, UFO

Specifications

Movement
Hand-Winding
Case Material
Two-Tone
Case Width
37mm
Case Thickness
10.3mm
Lug Width
19mm
Crystal
Sapphire
Bezel
Inner Rotating
Water Resistance
140m
Dial Color
Silver
Jewels
26j
Frequency
21,600 bph
Power Reserve
49 hours
Year
1991

Related Models

seikata-wm-be1a97682438