Seiko Cal. 5638 - 680

Released in 1978, the Cal. 5638 with design code 680 was part of Seiko's domestic market collection. It features a Black dial protected by a Mineral crystal and offers 90m of water resistance. [seikata-wm-6013de12fb39]

Also known as: Tuna

Specifications

Movement

Spring Drive

Case Material

Titanium

Case Width

35mm

Case Thickness

13.6mm

Lug Width

19mm

Crystal

Mineral

Bezel

Inner Rotating

Water Resistance

90m

Dial Color

Black

Jewels

19j

Frequency

21,600 bph

Power Reserve

36 hours

Year

1978

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