Seiko Cal. 6639 - 731

Seiko 6639-731

This Hand-Winding model from 1968 features a 36mm Hardlex-Coated Steel case. Powered by the 6639 caliber with 20j jewels beating at 21,600 bph, it delivers a 56 hours power reserve. [seikata-wm-c046245f3e57]

Specifications

Movement
Hand-Winding
Case Material
Hardlex-Coated Steel
Case Width
36mm
Case Thickness
12.2mm
Lug Width
22mm
Crystal
Hardlex
Bezel
Bidirectional
Water Resistance
170m
Dial Color
Burgundy
Jewels
20j
Frequency
21,600 bph
Power Reserve
56 hours
Year
1968

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seikata-wm-c046245f3e57