Seiko Cal. 6638 - 730

The Seiko 6638-730 represents an important milestone in Seiko's 1975 lineup. It features a Black dial protected by a Sapphire crystal and offers 130m of water resistance. [seikata-wm-3eca61ca1e2d]

Also known as: Tuna, Crown

Specifications

Movement

Hand-Winding

Case Material

Stainless Steel

Case Width

38mm

Case Thickness

12.5mm

Lug Width

22mm

Crystal

Sapphire

Bezel

Bidirectional

Water Resistance

130m

Dial Color

Black

Jewels

27j

Frequency

28,800 bph

Power Reserve

46 hours

Year

1975

Related Models

• Seiko 7129-846
• Seiko 6672-220
• Seiko 5684-179
• Seiko 4481-319
• Seiko 5279-653
• Seiko 3811-527
• Seiko 6335-921
• Seiko 6349-991
• Seiko 7126-554
• Seiko 5222-986
• Seiko 0720-947
• Seiko 4576-945