Seiko Cal. 6637 - 720

The 6637-720 is a sought-after Solar piece from Seiko's golden era. Powered by the 6637 caliber with 27j jewels beating at 28,800 bph, it delivers a 59 hours power reserve. [seikata-wm-1da440ba29b5]

Also known as: Bullhead, Goldfeather

Specifications

Movement

Solar

Case Material

Hardlex-Coated Steel

Case Width

37mm

Case Thickness

11.8mm

Lug Width

20mm

Crystal

Hardlex

Bezel

Fixed

Water Resistance

40m

Dial Color

Black

Jewels

27j

Frequency

28,800 bph

Power Reserve

59 hours

Year

1969

Related Models

• Seiko 7066-417
• Seiko 7110-437
• Seiko 6394-173
• Seiko 6321-962
• Seiko 0714-391
• Seiko 7155-720
• Seiko 4419-899
• Seiko 7092-515
• Seiko 4562-988
• Seiko 4468-642
• Seiko 6258-890
• Seiko 6115-956