Seiko Cal. 6640 - 154

The Seiko 6640-154 represents an important milestone in Seiko's 1974 lineup. Powered by the 6640 caliber with 33j jewels beating at 21,600 bph, it delivers a 56 hours power reserve. [seikata-wm-ee537c5e8083]

Also known as: Sumo

Specifications

Movement

Quartz

Case Material

Stainless Steel

Case Width

35mm

Case Thickness

9.8mm

Lug Width

20mm

Crystal

Sapphire

Bezel

Inner Rotating

Water Resistance

30m

Dial Color

Silver

Jewels

33j

Frequency

21,600 bph

Power Reserve

56 hours

Year

1974

Related Models

• Seiko 7163-201
• Seiko 7084-996
• Seiko 6170-850
• Seiko 6284-653
• Seiko 3883-267
• Seiko 6353-619
• Seiko 4425-551
• Seiko 3836-630
• Seiko 7046-526
• Seiko 7181-681
• Seiko 6349-608
• Seiko 5611-890