It does not crumple and cut the hair A round leather dog collar is perfect for everyday walking, training and using at exhibitions. The slip collar squeezes tightly the dogs neck when he moves forward fast. When the dog stops pulling the leash, the collar increases its size and stops tightening the neck. It does not cut and damage the dogs hair.The main task of the collar is to be durable and reliable. Slip Collar Length 40cm diameter 8mm