Seiko Cal. 6631 - 538

This Hand-Winding model from 1969 features a 42mm Two-Tone case. Powered by the 6631 caliber with 32j jewels beating at 28,800 bph, it delivers a 44 hours power reserve. [seikata-wm-3c6020c81581]

Also known as: Tuna

Specifications

Movement

Hand-Winding

Case Material

Two-Tone

Case Width

42mm

Case Thickness

8.1mm

Lug Width

19mm

Crystal

Acrylic

Bezel

Inner Rotating

Water Resistance

140m

Dial Color

Navy

Jewels

32j

Frequency

28,800 bph

Power Reserve

44 hours

Year

1969

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