Seiko Cal. 6640 - 361

The Seiko 6640-361 represents an important milestone in Seiko's 1976 lineup. Powered by the 6640 caliber with 31j jewels beating at 28,800 bph, it delivers a 50 hours power reserve. [seikata-wm-ba00af04005f]

Also known as: Golden Tuna

Specifications

Movement

Quartz

Case Material

Hardlex-Coated Steel

Case Width

37mm

Case Thickness

12.2mm

Lug Width

18mm

Crystal

Mineral

Bezel

Bidirectional

Water Resistance

140m

Dial Color

Navy

Jewels

31j

Frequency

28,800 bph

Power Reserve

50 hours

Year

1976

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