Seiko Cal. 3840 - 641

The Seiko 3840-641 represents an important milestone in Seiko's 1970 lineup. It features a Burgundy dial protected by a Hardlex crystal and offers 40m of water resistance. [seikata-wm-cd8b89a46265]

Also known as: Sumo, Bellmatic

Specifications

Movement

Spring Drive

Case Material

Hardlex-Coated Steel

Case Width

34mm

Case Thickness

14.4mm

Lug Width

21mm

Crystal

Hardlex

Bezel

Bidirectional

Water Resistance

40m

Dial Color

Burgundy

Jewels

21j

Frequency

36,000 bph

Power Reserve

44 hours

Year

1970

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