Seiko Cal. 6657 - 840

The Seiko 6657-840 represents an important milestone in Seiko's 1981 lineup. Powered by the 6657 caliber with 28j jewels beating at 28,800 bph, it delivers a 72 hours power reserve. [seikata-wm-d970ef3a630b]

Also known as: Sportsmatic, Crown

Specifications

Movement

Automatic

Case Material

PVD Black

Case Width

38mm

Case Thickness

10.2mm

Lug Width

21mm

Crystal

Hardlex

Bezel

Rotating

Water Resistance

140m

Dial Color

Navy

Jewels

28j

Frequency

28,800 bph

Power Reserve

72 hours

Year

1981

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