Seiko Cal. 6631 - 377

The 6631-377 is a sought-after Spring Drive piece from Seiko's golden era. The Bidirectional bezel and 39mm case give it a distinctive presence on the wrist. [seikata-wm-fabc985976a7]

Also known as: Bullhead

Specifications

Movement

Spring Drive

Case Material

Two-Tone

Case Width

39mm

Case Thickness

15.1mm

Lug Width

20mm

Crystal

Sapphire

Bezel

Bidirectional

Water Resistance

100m

Dial Color

Navy

Jewels

25j

Frequency

36,000 bph

Power Reserve

66 hours

Year

1966

Related Models

• Seiko 6251-636
• Seiko 0794-702
• Seiko 5289-986
• Seiko 7120-440
• Seiko 6297-306
• Seiko 4570-143
• Seiko 7130-855
• Seiko 6366-446
• Seiko 5642-855
• Seiko 6266-254
• Seiko 6275-472
• Seiko 6632-175