Seiko Cal. 6640 - 537

This Hand-Winding model from 1988 features a 35mm Two-Tone case. With its 18mm lug width and 8.7mm profile, it sits comfortably on most wrists. [seikata-wm-15bbd93ef270]

Also known as: Tuna, Rally

Specifications

Movement

Hand-Winding

Case Material

Two-Tone

Case Width

35mm

Case Thickness

8.7mm

Lug Width

18mm

Crystal

Acrylic

Bezel

Inner Rotating

Water Resistance

90m

Dial Color

Blue Sunburst

Jewels

31j

Frequency

28,800 bph

Power Reserve

61 hours

Year

1988

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