Seiko Cal. 6390 - 820

The Seiko 6390-820 represents an important milestone in Seiko's 1978 lineup. Powered by the 6390 caliber with 18j jewels beating at 21,600 bph, it delivers a 70 hours power reserve. [seikata-wm-88f8629f2bb0]

Also known as: Tuna, Sportsmatic

Specifications

Movement

Solar

Case Material

Stainless Steel

Case Width

41mm

Case Thickness

10.2mm

Lug Width

19mm

Crystal

Acrylic

Bezel

Inner Rotating

Water Resistance

180m

Dial Color

Black

Jewels

18j

Frequency

21,600 bph

Power Reserve

70 hours

Year

1978

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