Martingale collars are a option for dog owners that is highly recommended by trainers. At Petature, we offer a wide selection of these amazing collars. When pulled, the collar will tighten. Once the pulling has stopped, the collar relaxes thus preventing your dog from escaping or backing out from his collar. Our Martingales dog collars are available in many beautiful colors and sizes, so that you can choose the one that fits your dog best.