Has anyone heard of the Don Sullivan training system ? How does it work ? Does it work? They
show a training collar but say's it isn't a shock
collar so wondered how it worked. Saw a comerical about it so was curious.

From the info on the site, the collar is a type of prong collar. When it is tightened through the application of a leash...or as he calls it, a "training line", the links put acute pressure on the dog's neck.