Seiko Cal. 5661 - 391

The Seiko 5661-391 represents an important milestone in Seiko's 1968 lineup. Powered by the 5661 caliber with 21j jewels beating at 36,000 bph, it delivers a 53 hours power reserve. [seikata-wm-dce57efc6cdc]

Also known as: Monster, Sumo

Specifications

Movement

Solar

Case Material

Titanium

Case Width

44mm

Case Thickness

12.9mm

Lug Width

21mm

Crystal

Mineral

Bezel

Rotating

Water Resistance

160m

Dial Color

Burgundy

Jewels

21j

Frequency

36,000 bph

Power Reserve

53 hours

Year

1968

Related Models

• Seiko 6271-899
• Seiko 6366-607
• Seiko 6324-161
• Seiko 0780-352
• Seiko 7050-264
• Seiko 6386-715
• Seiko 6137-328
• Seiko 7022-403
• Seiko 5619-308
• Seiko 5231-678
• Seiko 4450-474
• Seiko 4566-740