Seiko Cal. 6631 - 557

This Spring Drive model from 1965 features a 38mm PVD Black case. With its 20mm lug width and 13.1mm profile, it sits comfortably on most wrists. [seikata-wm-0dc0691732d5]

Specifications

Movement

Spring Drive

Case Material

PVD Black

Case Width

38mm

Case Thickness

13.1mm

Lug Width

20mm

Crystal

Sapphire

Bezel

Inner Rotating

Water Resistance

110m

Dial Color

Navy

Jewels

29j

Frequency

36,000 bph

Power Reserve

48 hours

Year

1965

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