Seiko Cal. 6638 - 340

This Spring Drive model from 1971 features a 44mm Stainless Steel case. With its 19mm lug width and 8.6mm profile, it sits comfortably on most wrists. [seikata-wm-bbcc79ff2a9f]

Also known as: Helmet, UFO

Specifications

Movement

Spring Drive

Case Material

Stainless Steel

Case Width

44mm

Case Thickness

8.6mm

Lug Width

19mm

Crystal

Acrylic

Bezel

Inner Rotating

Water Resistance

30m

Dial Color

Green

Jewels

35j

Frequency

21,600 bph

Power Reserve

66 hours

Year

1971

Related Models

• Seiko 4433-769
• Seiko 3828-635
• Seiko 6272-960
• Seiko 6677-543
• Seiko 4560-204
• Seiko 4545-165
• Seiko 5672-712
• Seiko 0742-286
• Seiko 5222-643
• Seiko 4559-890
• Seiko 5613-424
• Seiko 5279-281