I've read about this on here before and after many months of pulling and tugging, I finally got one for Sam. The manufacturers describe it as power steering for your dog and I reckon they're absolutely correct. Bought it yesterday and fitted it. Had lots of unhappy pulling and tugging on his face. Put it on again this morning and after some initial pulling and tugging, we went for a walk and Sam walked beside me on a loose tension-less leash the whole time. I am SO impressed. No prompting, no correction required. WOW!