Seiko Cal. 3870 - 421

Released in 1971, the Cal. 3870 with design code 421 was part of Seiko's domestic market collection. The Rotating bezel and 37mm case give it a distinctive presence on the wrist. [seikata-wm-cde9527bee0b]

Also known as: Tuna, Baby Tuna

Specifications

Movement

Automatic

Case Material

Two-Tone

Case Width

37mm

Case Thickness

15.9mm

Lug Width

21mm

Crystal

Hardlex

Bezel

Rotating

Water Resistance

180m

Dial Color

Blue Sunburst

Jewels

23j

Frequency

21,600 bph

Power Reserve

67 hours

Year

1971

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