Seiko Cal. 6638 - 740

The 6638-740 is a sought-after Spring Drive piece from Seiko's golden era. Powered by the 6638 caliber with 21j jewels beating at 21,600 bph, it delivers a 45 hours power reserve. [seikata-wm-a077d1570b0b]

Also known as: Rally

Specifications

Movement

Spring Drive

Case Material

Hardlex-Coated Steel

Case Width

45mm

Case Thickness

13.3mm

Lug Width

21mm

Crystal

Mineral

Bezel

Bidirectional

Water Resistance

200m

Dial Color

White

Jewels

21j

Frequency

21,600 bph

Power Reserve

45 hours

Year

1983

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