Seiko Cal. 0721 - 637

The Seiko 0721-637 represents an important milestone in Seiko's 1974 lineup. The Coin-Edge bezel and 43mm case give it a distinctive presence on the wrist. [seikata-wm-1d9cb88c5942]

Also known as: Sumo, Bullhead

Specifications

Movement

Automatic

Case Material

Two-Tone

Case Width

43mm

Case Thickness

9.9mm

Lug Width

22mm

Crystal

Sapphire

Bezel

Coin-Edge

Water Resistance

80m

Dial Color

Blue Sunburst

Jewels

17j

Frequency

28,800 bph

Power Reserve

69 hours

Year

1974

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