My two dogs are have a high prey drive, and they weigh about 55 pounds each. We run together several days a week and I was using halti collars recommended by my vet. It helped more than a normal collar when they pull hard, but they tended to still pull when excited and would get rubs from the nylon on their noses. We have taken obedience classes and are working on walking on loose leash which they do 95 percent of the time. That ONE squirrel making a suicidal bid across the road in front of us though is all it takes to get them going. I normally can handle it, but I have a shoulder injury now that isn't enjoying the yanking. I ordered these collars on the recommendation from our trainer. It is My two dogs are have a high prey drive, and they weigh about 55 pounds each. We run together several days a week and I was using halti collars recommended by my vet. It helped more than a normal collar when they pull hard, but they tended to still pull when excited and would get rubs from the nylon on their noses. We have taken obedience classes and are working on walking on loose leash which they do 95 percent of the time. That ONE squirrel making a suicidal bid across the road in front of us though is all it takes to get them going. I normally can handle it, but I have a shoulder injury now that isn't enjoying the yanking. I ordered these collars on the recommendation from our trainer. It is amazing how well these work. They may yank a little, but as soon as they feel the pinch, they back off. I read that it works as a momma dog's nip would remind them when they get out of line as pups. I think it does work, as they don't appear to be in pain, it's just enough to say "hey, no. Not appropriate behavior." I have checked their necks after every walk/ run and they have no sores or red marks. It is important to buy a herm sprenger collar or equivalent. Cheap knock offs can have extremely sharp prongs. These are blunt and the action is not a poking, but a squeeze of the prongs together. Excellent product. Highly recommend for strong pullers. … more