Seiko Cal. 6640 - 256

Released in 1974, the Cal. 6640 with design code 256 was part of Seiko's domestic market collection. It features a Black dial protected by a Mineral crystal and offers 190m of water resistance. [seikata-wm-44d5dd7cea5b]

Also known as: Turtle, Sea Horse

Specifications

Movement

Kinetic

Case Material

Stainless Steel

Case Width

37mm

Case Thickness

9.9mm

Lug Width

22mm

Crystal

Mineral

Bezel

Fixed

Water Resistance

190m

Dial Color

Black

Jewels

36j

Frequency

21,600 bph

Power Reserve

38 hours

Year

1974

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