This questioned was answered on a Horse Whisperers Discussion Forum bulletin board by: Caroline on October 05, 1999 at 19:30:55:
Monty Roberts has two training items that he’s put his name on – “gimmicks” we might call them, as they are above and beyond the severity that we would normally use on a horse. One is his “Dually” halter, which is a glorified “war bridle”, which tightens down and puts pressure on a horse’s head when pulled.
The other is his “Buck-stop”. I haven’t seen one, but have the idea that somehow a rope placed against the horse’s gum-line, runs up between the horse’s ears, along the top of his neck to the saddle, so when the horse puts his head down to buck, his mouth is punished.
I do object to Monty’s marketing of these devices to the general audiences that he performs to. I’m sure that in the hands of some experienced people, that they could be effective at times. But Monty indicates that they can be easily used by anyone – dangerous advice, in my way of thinking. Caroline