Seiko Cal. 6640 - 721

Seiko 6640-721

The 6640-721 is a sought-after Kinetic piece from Seiko's golden era. Powered by the 6640 caliber with 25j jewels beating at 36,000 bph, it delivers a 47 hours power reserve. [seikata-wm-37bd529c65ca]

Also known as: Tuna, Baby Tuna

Specifications

Movement
Kinetic
Case Material
Stainless Steel
Case Width
42mm
Case Thickness
13.1mm
Lug Width
18mm
Crystal
Sapphire
Bezel
Bidirectional
Water Resistance
60m
Dial Color
Black
Jewels
25j
Frequency
36,000 bph
Power Reserve
47 hours
Year
1990

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seikata-wm-37bd529c65ca