Seiko Cal. 6643 - 964

The Seiko 6643-964 represents an important milestone in Seiko's 1978 lineup. It features a Black dial protected by a Mineral crystal and offers 90m of water resistance. [seikata-wm-1c05178c89dd]

Also known as: Monster, Tuna

Specifications

Movement

Solar

Case Material

Gold-Plated

Case Width

42mm

Case Thickness

9.5mm

Lug Width

20mm

Crystal

Mineral

Bezel

Inner Rotating

Water Resistance

90m

Dial Color

Black

Jewels

30j

Frequency

21,600 bph

Power Reserve

53 hours

Year

1978

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