Seiko Cal. 6631 - 528

This Hand-Winding model from 1980 features a 37mm Gold-Plated case. Powered by the 6631 caliber with 17j jewels beating at 36,000 bph, it delivers a 48 hours power reserve. [seikata-wm-efabd5e5cd2b]

Also known as: Sumo, Bullhead

Specifications

Movement

Hand-Winding

Case Material

Gold-Plated

Case Width

37mm

Case Thickness

13.9mm

Lug Width

22mm

Crystal

Sapphire

Bezel

Fixed

Water Resistance

160m

Dial Color

White

Jewels

17j

Frequency

36,000 bph

Power Reserve

48 hours

Year

1980

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