Seiko Cal. 6635 - 644

The Seiko 6635-644 represents an important milestone in Seiko's 1971 lineup. It features a Navy dial protected by a Acrylic crystal and offers 70m of water resistance. [seikata-wm-249fa2c2121f]

Also known as: Bullhead

Specifications

Movement

Hand-Winding

Case Material

Hardlex-Coated Steel

Case Width

42mm

Case Thickness

15.7mm

Lug Width

18mm

Crystal

Acrylic

Bezel

Rotating

Water Resistance

70m

Dial Color

Navy

Jewels

19j

Frequency

21,600 bph

Power Reserve

65 hours

Year

1971

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