Seiko Cal. 6640 - 511

The Seiko 6640-511 represents an important milestone in Seiko's 1978 lineup. The Bidirectional bezel and 46mm case give it a distinctive presence on the wrist. [seikata-wm-991ca40aaff7]

Also known as: Bullhead, World Timer

Specifications

Movement

Spring Drive

Case Material

Two-Tone

Case Width

46mm

Case Thickness

12.3mm

Lug Width

18mm

Crystal

Hardlex

Bezel

Bidirectional

Water Resistance

150m

Dial Color

Green

Jewels

30j

Frequency

28,800 bph

Power Reserve

44 hours

Year

1978

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