Seiko Cal. 6641 - 731

The Seiko 6641-731 represents an important milestone in Seiko's 1973 lineup. Powered by the 6641 caliber with 30j jewels beating at 36,000 bph, it delivers a 37 hours power reserve. [seikata-wm-3092e3c84652]

Also known as: Turtle, Sumo

Specifications

Movement

Hand-Winding

Case Material

PVD Black

Case Width

37mm

Case Thickness

9.6mm

Lug Width

21mm

Crystal

Sapphire

Bezel

Coin-Edge

Water Resistance

170m

Dial Color

Silver

Jewels

30j

Frequency

36,000 bph

Power Reserve

37 hours

Year

1973

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