Seiko Cal. 6643 - 820

The 6643-820 is a sought-after Hand-Winding piece from Seiko's golden era. It features a Green dial protected by a Hardlex crystal and offers 70m of water resistance. [seikata-wm-c5ae12393d9e]

Also known as: Monster, Tuna

Specifications

Movement

Hand-Winding

Case Material

PVD Black

Case Width

44mm

Case Thickness

9.8mm

Lug Width

20mm

Crystal

Hardlex

Bezel

Fixed

Water Resistance

70m

Dial Color

Green

Jewels

31j

Frequency

36,000 bph

Power Reserve

56 hours

Year

1965

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