Seiko Cal. 6643 - 528

This Spring Drive model from 1983 features a 41mm Hardlex-Coated Steel case. With its 20mm lug width and 13.3mm profile, it sits comfortably on most wrists. [seikata-wm-26ab6fe4434b]

Also known as: Tuna, Bullhead

Specifications

Movement

Spring Drive

Case Material

Hardlex-Coated Steel

Case Width

41mm

Case Thickness

13.3mm

Lug Width

20mm

Crystal

Sapphire

Bezel

Fixed

Water Resistance

100m

Dial Color

Silver

Jewels

23j

Frequency

36,000 bph

Power Reserve

69 hours

Year

1983

Related Models

• Seiko 6140-550
• Seiko 6376-279
• Seiko 7131-779
• Seiko 3863-250
• Seiko 3865-478
• Seiko 3899-103
• Seiko 7066-886
• Seiko 3897-534
• Seiko 7090-122
• Seiko 5668-464
• Seiko 6197-477
• Seiko 5211-844