My original review of this collar was a 1 star and it was terrible because it did NOT work. I am changing my review because the seller not only gave me back my money but sent me a "new, revised" collar that seems to work well on my hound pup. The seller went above and beyond to check the product, change it and send me a free one to try. I appreciate that. The fact that the new collar works is great. I hit the shock exactly twice with the hound and haven't needed to again, since she is responding to the beep and vibrate. So the new revised shock collar gets my approval.