Herm Sprenger Ultra-Plus Training Dog Prong Collar, 18-in neck, 3.0-mm wide; Give yourself a little extra help with the Herm Sprenger Ultra-Plus Prong Training Dog Collar. A safe and practical tool for training, this collar is designed to let dogs know when it’s time to heel. The blunt prongs are effective without causing pain, and the patented center plate construction and symmetrical placements act as a natural point of contact for clear communication. It’s great for taking large dogs or tough pullers on a walk, protecting you and them from getting into a dangerous situation. Replacement links are available if you need to add more to for a custom fit, and can also be removed to adjust size.