Seiko Cal. 5631 - 691

The 5631-691 is a sought-after Quartz piece from Seiko's golden era. Powered by the 5631 caliber with 31j jewels beating at 36,000 bph, it delivers a 54 hours power reserve. [seikata-wm-1fb35de98f75]

Also known as: UFO, Bellmatic

Specifications

Movement

Quartz

Case Material

PVD Black

Case Width

42mm

Case Thickness

10.9mm

Lug Width

22mm

Crystal

Mineral

Bezel

Coin-Edge

Water Resistance

90m

Dial Color

Blue Sunburst

Jewels

31j

Frequency

36,000 bph

Power Reserve

54 hours

Year

1992

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