This is what they call a pronged collar, I have heard people swear by them, they are not fitted tight but if the dog pulls it puts pressure on the dog hence it stops pulling, I personally think they are terrible, but apparently no harm comes to the dog wearing them and if used correctly work, I have had many an argument with people that use these, but in their mind its not hurting the dog, they can walk their dog with ease, so they dont think there is anything wrong in using them
they tend to get used on thick coated animals
Mo