Seiko Cal. 6641 - 750

Released in 1968, the Cal. 6641 with design code 750 was part of Seiko's domestic market collection. The Inner Rotating bezel and 40mm case give it a distinctive presence on the wrist. [seikata-wm-0b0add928aad]

Also known as: Sumo, World Timer

Specifications

Movement

Hand-Winding

Case Material

Titanium

Case Width

40mm

Case Thickness

15.1mm

Lug Width

20mm

Crystal

Hardlex

Bezel

Inner Rotating

Water Resistance

60m

Dial Color

Blue Sunburst

Jewels

26j

Frequency

28,800 bph

Power Reserve

53 hours

Year

1968

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