Seiko Cal. 6631 - 637

The 6631-637 is a sought-after Quartz piece from Seiko's golden era. It features a Black dial protected by a Acrylic crystal and offers 110m of water resistance. [seikata-wm-c9d1ad424157]

Also known as: Bellmatic, Baby Tuna

Specifications

Movement

Quartz

Case Material

Two-Tone

Case Width

38mm

Case Thickness

10.6mm

Lug Width

21mm

Crystal

Acrylic

Bezel

Bidirectional

Water Resistance

110m

Dial Color

Black

Jewels

28j

Frequency

28,800 bph

Power Reserve

65 hours

Year

1981

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