Seiko Cal. 5631 - 171

The Seiko 5631-171 represents an important milestone in Seiko's 1975 lineup. It features a Black dial protected by a Mineral crystal and offers 40m of water resistance. [seikata-wm-024b7ecb8056]

Also known as: Sumo, Emperor

Specifications

Movement

Spring Drive

Case Material

PVD Black

Case Width

37mm

Case Thickness

15.5mm

Lug Width

20mm

Crystal

Mineral

Bezel

Bidirectional

Water Resistance

40m

Dial Color

Black

Jewels

30j

Frequency

28,800 bph

Power Reserve

65 hours

Year

1975

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