Seiko Cal. 6640 - 669

The Seiko 6640-669 represents an important milestone in Seiko's 1985 lineup. Powered by the 6640 caliber with 31j jewels beating at 21,600 bph, it delivers a 55 hours power reserve. [seikata-wm-1701b15bc820]

Also known as: World Timer, Navigator

Specifications

Movement

Automatic

Case Material

Hardlex-Coated Steel

Case Width

37mm

Case Thickness

10.1mm

Lug Width

21mm

Crystal

Sapphire

Bezel

Coin-Edge

Water Resistance

40m

Dial Color

Burgundy

Jewels

31j

Frequency

21,600 bph

Power Reserve

55 hours

Year

1985

Related Models

• Seiko 6367-594
• Seiko 5688-577
• Seiko 6148-544
• Seiko 7133-448
• Seiko 4468-852
• Seiko 0792-817
• Seiko 6274-942
• Seiko 6374-544
• Seiko 7194-500
• Seiko 7023-725
• Seiko 5275-444
• Seiko 5679-117