AKA
Dominant Dog Collars
AKA
Nylon Choke Collars
These are simple braided nylon rope collars that are used by many professionals to train aggressive or over reactive dogs.
They are not used as a correction collar but rather a collar to take drive out of a dog and restore control.
If you do not know how to use one of these collars, best dont buy one, just like any training collar.
You will see a similar one used on the Dog Whisperer show.