Seiko Cal. 6690 - 637

The 6690-637 is a sought-after Automatic piece from Seiko's golden era. It features a Green dial protected by a Hardlex crystal and offers 140m of water resistance. [seikata-wm-6df99c5b8d11]

Also known as: Turtle, Sportsmatic

Specifications

Movement

Automatic

Case Material

Hardlex-Coated Steel

Case Width

40mm

Case Thickness

9.3mm

Lug Width

18mm

Crystal

Hardlex

Bezel

Fixed

Water Resistance

140m

Dial Color

Green

Jewels

31j

Frequency

28,800 bph

Power Reserve

43 hours

Year

1975

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