Seiko Cal. 4521 - 731

The 4521-731 is a sought-after Spring Drive piece from Seiko's golden era. Powered by the 4521 caliber with 26j jewels beating at 28,800 bph, it delivers a 47 hours power reserve. [seikata-wm-f2b65dde55fa]

Also known as: Turtle, World Timer

Specifications

Movement

Spring Drive

Case Material

Two-Tone

Case Width

37mm

Case Thickness

8.2mm

Lug Width

19mm

Crystal

Mineral

Bezel

Bidirectional

Water Resistance

130m

Dial Color

Silver

Jewels

26j

Frequency

28,800 bph

Power Reserve

47 hours

Year

1979

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