Seiko Cal. 6644 - 657

The Seiko 6644-657 represents an important milestone in Seiko's 1977 lineup. It features a Green dial protected by a Sapphire crystal and offers 140m of water resistance. [seikata-wm-6ef5d16fd366]

Specifications

Movement

Hand-Winding

Case Material

Two-Tone

Case Width

43mm

Case Thickness

10.0mm

Lug Width

20mm

Crystal

Sapphire

Bezel

Bidirectional

Water Resistance

140m

Dial Color

Green

Jewels

28j

Frequency

28,800 bph

Power Reserve

40 hours

Year

1977

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