Seiko Cal. 6631 - 987

The 6631-987 is a sought-after Hand-Winding piece from Seiko's golden era. Powered by the 6631 caliber with 28j jewels beating at 28,800 bph, it delivers a 66 hours power reserve. [seikata-wm-b82d25247ad2]

Also known as: Turtle, Navigator

Specifications

Movement

Hand-Winding

Case Material

Titanium

Case Width

37mm

Case Thickness

9.9mm

Lug Width

19mm

Crystal

Mineral

Bezel

Inner Rotating

Water Resistance

110m

Dial Color

Blue Sunburst

Jewels

28j

Frequency

28,800 bph

Power Reserve

66 hours

Year

1991

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