Seiko Cal. 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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