Seiko Cal. 6657 - 635

This Spring Drive model from 1981 features a 39mm Hardlex-Coated Steel case. The Bidirectional bezel and 39mm case give it a distinctive presence on the wrist. [seikata-wm-dc6ba4918937]

Also known as: Helmet

Specifications

Movement

Spring Drive

Case Material

Hardlex-Coated Steel

Case Width

39mm

Case Thickness

13.0mm

Lug Width

21mm

Crystal

Mineral

Bezel

Bidirectional

Water Resistance

40m

Dial Color

Green

Jewels

34j

Frequency

21,600 bph

Power Reserve

66 hours

Year

1981

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