Seiko Cal. 4521 - 358

The 4521-358 is a sought-after Spring Drive piece from Seiko's golden era. Powered by the 4521 caliber with 21j jewels beating at 21,600 bph, it delivers a 56 hours power reserve. [seikata-wm-c4ecb4dcf5ca]

Also known as: Monster, Tuna

Specifications

Movement

Spring Drive

Case Material

PVD Black

Case Width

43mm

Case Thickness

12.8mm

Lug Width

22mm

Crystal

Acrylic

Bezel

Inner Rotating

Water Resistance

170m

Dial Color

Blue Sunburst

Jewels

21j

Frequency

21,600 bph

Power Reserve

56 hours

Year

1966

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