Seiko Cal. 4431 - 813

This Automatic model from 1973 features a 41mm Two-Tone case. Powered by the 4431 caliber with 20j jewels beating at 21,600 bph, it delivers a 40 hours power reserve. [seikata-wm-c5374c5b86b1]

Also known as: Baby Tuna

Specifications

Movement

Automatic

Case Material

Two-Tone

Case Width

41mm

Case Thickness

10.6mm

Lug Width

20mm

Crystal

Sapphire

Bezel

Fixed

Water Resistance

100m

Dial Color

Champagne

Jewels

20j

Frequency

21,600 bph

Power Reserve

40 hours

Year

1973

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