Seiko Cal. 6641 - 731

Seiko 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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seikata-wm-3092e3c84652