Seiko Cal. 5644 - 261

The Seiko 5644-261 represents an important milestone in Seiko's 1977 lineup. It features a Blue Sunburst dial protected by a Acrylic crystal and offers 50m of water resistance. [seikata-wm-6e340e8c94ee]

Also known as: Monster, Sumo

Specifications

Movement

Spring Drive

Case Material

Stainless Steel

Case Width

37mm

Case Thickness

11.5mm

Lug Width

18mm

Crystal

Acrylic

Bezel

Bidirectional

Water Resistance

50m

Dial Color

Blue Sunburst

Jewels

26j

Frequency

36,000 bph

Power Reserve

60 hours

Year

1977

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