Seiko Cal. 6643 - 687

The Seiko 6643-687 represents an important milestone in Seiko's 1977 lineup. It features a Navy dial protected by a Sapphire crystal and offers 40m of water resistance. [seikata-wm-b99331ca98ab]

Also known as: Samurai, Tuna

Specifications

Movement

Spring Drive

Case Material

Hardlex-Coated Steel

Case Width

36mm

Case Thickness

8.4mm

Lug Width

22mm

Crystal

Sapphire

Bezel

Bidirectional

Water Resistance

40m

Dial Color

Navy

Jewels

19j

Frequency

21,600 bph

Power Reserve

51 hours

Year

1977

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