Seiko Cal. 5637 - 437

This Hand-Winding model from 1971 features a 36mm Hardlex-Coated Steel case. Powered by the 5637 caliber with 26j jewels beating at 36,000 bph, it delivers a 40 hours power reserve. [seikata-wm-5b114a7a0e83]

Also known as: Sumo, Tuna

Specifications

Movement

Hand-Winding

Case Material

Hardlex-Coated Steel

Case Width

36mm

Case Thickness

10.6mm

Lug Width

20mm

Crystal

Mineral

Bezel

Coin-Edge

Water Resistance

110m

Dial Color

Blue Sunburst

Jewels

26j

Frequency

36,000 bph

Power Reserve

40 hours

Year

1971

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