Seiko Cal. 6640 - 931

Released in 1985, the Cal. 6640 with design code 931 was part of Seiko's domestic market collection. It features a Cream dial protected by a Sapphire crystal and offers 60m of water resistance. [seikata-wm-eff73ce5198e]

Also known as: Sumo

Specifications

Movement

Kinetic

Case Material

PVD Black

Case Width

38mm

Case Thickness

11.7mm

Lug Width

21mm

Crystal

Sapphire

Bezel

Fixed

Water Resistance

60m

Dial Color

Cream

Jewels

29j

Frequency

21,600 bph

Power Reserve

46 hours

Year

1985

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