Seiko Cal. 4420 - 721

The Seiko 4420-721 represents an important milestone in Seiko's 1977 lineup. Powered by the 4420 caliber with 22j jewels beating at 36,000 bph, it delivers a 47 hours power reserve. [seikata-wm-defbb254e2a1]

Also known as: Bullhead

Specifications

Movement

Hand-Winding

Case Material

Two-Tone

Case Width

35mm

Case Thickness

11.8mm

Lug Width

21mm

Crystal

Mineral

Bezel

Inner Rotating

Water Resistance

140m

Dial Color

Champagne

Jewels

22j

Frequency

36,000 bph

Power Reserve

47 hours

Year

1977

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