Seiko Cal. 6640 - 311

Seiko 6640-311

The 6640-311 is a sought-after Quartz piece from Seiko's golden era. Powered by the 6640 caliber with 22j jewels beating at 28,800 bph, it delivers a 71 hours power reserve. [seikata-wm-7c9451fef1b1]

Also known as: Turtle, Sumo

Specifications

Movement
Quartz
Case Material
PVD Black
Case Width
38mm
Case Thickness
11.6mm
Lug Width
21mm
Crystal
Mineral
Bezel
Fixed
Water Resistance
150m
Dial Color
White
Jewels
22j
Frequency
28,800 bph
Power Reserve
71 hours
Year
1981

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