Seiko Cal. 5661 - 401

The 5661-401 is a sought-after Spring Drive piece from Seiko's golden era. Powered by the 5661 caliber with 25j jewels beating at 28,800 bph, it delivers a 41 hours power reserve. [seikata-wm-c1c9a11be8a1]

Also known as: Monster

Specifications

Movement

Spring Drive

Case Material

Stainless Steel

Case Width

39mm

Case Thickness

9.3mm

Lug Width

19mm

Crystal

Sapphire

Bezel

Coin-Edge

Water Resistance

30m

Dial Color

Green

Jewels

25j

Frequency

28,800 bph

Power Reserve

41 hours

Year

1965

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