Seiko Cal. 4550 - 640

The 4550-640 is a sought-after Quartz piece from Seiko's golden era. Powered by the 4550 caliber with 21j jewels beating at 21,600 bph, it delivers a 63 hours power reserve. [seikata-wm-92d63ed69e0c]

Also known as: Helmet

Specifications

Movement

Quartz

Case Material

Gold-Plated

Case Width

46mm

Case Thickness

9.9mm

Lug Width

18mm

Crystal

Mineral

Bezel

Bidirectional

Water Resistance

190m

Dial Color

White

Jewels

21j

Frequency

21,600 bph

Power Reserve

63 hours

Year

1974

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