Seiko Cal. 5661 - 739

The 5661-739 is a sought-after Spring Drive piece from Seiko's golden era. Powered by the 5661 caliber with 23j jewels beating at 21,600 bph, it delivers a 65 hours power reserve. [seikata-wm-49abf2da8ad2]

Also known as: Helmet

Specifications

Movement

Spring Drive

Case Material

Stainless Steel

Case Width

35mm

Case Thickness

8.5mm

Lug Width

21mm

Crystal

Mineral

Bezel

Fixed

Water Resistance

170m

Dial Color

Black

Jewels

23j

Frequency

21,600 bph

Power Reserve

65 hours

Year

1978

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