Vetsupply: The Canny Colossus Collar is specially designed to stop top large breed dogs from pulling on the leash, allowing even the worst pullers to be transformed into happy and well-behaved dogs. It is an easy-to-use, safe and comfortable collar that is made to fit your large dog perfectly. Its unique design lets the collar stay in place and does not ride up into your dog\'s eyes to cause distress or discomfort.