Seiko Cal. 6631 - 903

The Seiko 6631-903 represents an important milestone in Seiko's 1978 lineup. Powered by the 6631 caliber with 20j jewels beating at 28,800 bph, it delivers a 65 hours power reserve. [seikata-wm-e5a5cd151e5a]

Also known as: Crown, Arnie

Specifications

Movement

Spring Drive

Case Material

Two-Tone

Case Width

42mm

Case Thickness

12.9mm

Lug Width

20mm

Crystal

Sapphire

Bezel

Fixed

Water Resistance

50m

Dial Color

Burgundy

Jewels

20j

Frequency

28,800 bph

Power Reserve

65 hours

Year

1978

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