Seiko Cal. 4537 - 661

The Seiko 4537-661 represents an important milestone in Seiko's 1970 lineup. With its 21mm lug width and 11.2mm profile, it sits comfortably on most wrists. [seikata-wm-4efcc0f83bd3]

Also known as: Sumo, Bullhead

Specifications

Movement

Quartz

Case Material

Gold-Plated

Case Width

44mm

Case Thickness

11.2mm

Lug Width

21mm

Crystal

Acrylic

Bezel

Fixed

Water Resistance

150m

Dial Color

Navy

Jewels

21j

Frequency

36,000 bph

Power Reserve

66 hours

Year

1970

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