Seiko Cal. 6647 - 640

Released in 1970, the Cal. 6647 with design code 640 was part of Seiko's domestic market collection. The Inner Rotating bezel and 41mm case give it a distinctive presence on the wrist. [seikata-wm-11ebd06fd01c]

Also known as: Monster, Emperor

Specifications

Movement

Quartz

Case Material

Two-Tone

Case Width

41mm

Case Thickness

11.6mm

Lug Width

19mm

Crystal

Sapphire

Bezel

Inner Rotating

Water Resistance

170m

Dial Color

Burgundy

Jewels

23j

Frequency

21,600 bph

Power Reserve

56 hours

Year

1970

Related Models

• Seiko 6196-788
• Seiko 6112-720
• Seiko 6641-454
• Seiko 7191-315
• Seiko 7010-555
• Seiko 6140-543
• Seiko 5299-403
• Seiko 6244-892
• Seiko 6141-663
• Seiko 6292-643
• Seiko 6364-746
• Seiko 4457-142