Seiko Cal. 0721 - 637

The Seiko 0721-637 represents an important milestone in Seiko's 1967 lineup. Powered by the 0721 caliber with 21j jewels beating at 28,800 bph, it delivers a 48 hours power reserve. [seikata-wm-e7a425f37c02]

Also known as: Samurai, Crown

Specifications

Movement

Hand-Winding

Case Material

PVD Black

Case Width

40mm

Case Thickness

15.9mm

Lug Width

22mm

Crystal

Sapphire

Bezel

Bidirectional

Water Resistance

170m

Dial Color

Green

Jewels

21j

Frequency

28,800 bph

Power Reserve

48 hours

Year

1967

Related Models

• Seiko 5212-774
• Seiko 4481-566
• Seiko 3875-549
• Seiko 7012-427
• Seiko 0765-271
• Seiko 6653-272
• Seiko 5620-539
• Seiko 7141-442
• Seiko 4447-814
• Seiko 6676-938
• Seiko 5231-708
• Seiko 4588-616