Seiko Cal. 3857 - 631

The 3857-631 is a sought-after Spring Drive piece from Seiko's golden era. Powered by the 3857 caliber with 29j jewels beating at 36,000 bph, it delivers a 65 hours power reserve. [seikata-wm-affb97c41410]

Also known as: Bellmatic

Specifications

Movement

Spring Drive

Case Material

Two-Tone

Case Width

42mm

Case Thickness

13.5mm

Lug Width

20mm

Crystal

Hardlex

Bezel

Bidirectional

Water Resistance

120m

Dial Color

Blue Sunburst

Jewels

29j

Frequency

36,000 bph

Power Reserve

65 hours

Year

1976

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