Seiko Cal. 6640 - 307

The 6640-307 is a sought-after Spring Drive piece from Seiko's golden era. With its 19mm lug width and 15.1mm profile, it sits comfortably on most wrists. [seikata-wm-0a89fa16b299]

Also known as: Silverwave, Crown

Specifications

Movement

Spring Drive

Case Material

Two-Tone

Case Width

39mm

Case Thickness

15.1mm

Lug Width

19mm

Crystal

Sapphire

Bezel

Bidirectional

Water Resistance

40m

Dial Color

Green

Jewels

31j

Frequency

28,800 bph

Power Reserve

46 hours

Year

1991

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