Seiko Cal. 5631 - 870

Released in 1969, the Cal. 5631 with design code 870 was part of Seiko's domestic market collection. It features a Black dial protected by a Mineral crystal and offers 140m of water resistance. [seikata-wm-a5b7dd07ca5e]

Also known as: Sumo, Bullhead

Specifications

Movement

Kinetic

Case Material

Gold-Plated

Case Width

46mm

Case Thickness

13.1mm

Lug Width

18mm

Crystal

Mineral

Bezel

Coin-Edge

Water Resistance

140m

Dial Color

Black

Jewels

18j

Frequency

28,800 bph

Power Reserve

57 hours

Year

1969

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