Seiko Cal. 5641 - 731

The 5641-731 is a sought-after Spring Drive piece from Seiko's golden era. With its 21mm lug width and 10.9mm profile, it sits comfortably on most wrists. [seikata-wm-9f0e28bcf0dc]

Also known as: Helmet

Specifications

Movement

Spring Drive

Case Material

Hardlex-Coated Steel

Case Width

45mm

Case Thickness

10.9mm

Lug Width

21mm

Crystal

Hardlex

Bezel

Coin-Edge

Water Resistance

50m

Dial Color

Silver

Jewels

24j

Frequency

21,600 bph

Power Reserve

42 hours

Year

1981

Related Models

• Seiko 0731-257
• Seiko 3856-490
• Seiko 6338-310
• Seiko 6221-651
• Seiko 7147-559
• Seiko 6284-404
• Seiko 6198-373
• Seiko 3882-181
• Seiko 5259-592
• Seiko 3876-467
• Seiko 6627-747
• Seiko 4575-245