Seiko Cal. 6631 - 856

The Seiko 6631-856 represents an important milestone in Seiko's 1975 lineup. The Bidirectional bezel and 34mm case give it a distinctive presence on the wrist. [seikata-wm-e71b9de93418]

Also known as: Sumo, Bullhead

Specifications

Movement

Automatic

Case Material

Two-Tone

Case Width

34mm

Case Thickness

13.5mm

Lug Width

20mm

Crystal

Sapphire

Bezel

Bidirectional

Water Resistance

120m

Dial Color

Silver

Jewels

24j

Frequency

28,800 bph

Power Reserve

62 hours

Year

1975

Related Models

• Seiko 6328-444
• Seiko 3823-739
• Seiko 5623-308
• Seiko 4557-534
• Seiko 6159-137
• Seiko 4553-858
• Seiko 7091-693
• Seiko 6117-846
• Seiko 6688-432
• Seiko 4563-568
• Seiko 3812-900
• Seiko 3864-998