The SmartLeash retractable leash automatically stops a dog when he or she tries to suddenly run or lunge. It locks quickly, safely and automatically and stays locked as long as the dog has tension on the leash. When a dog releases tension, SmartLeash resets instantly. There is also a manual lock as well as a self-locking system on the product giving the dog owner flexibility to control their dog as they wish. The Smartleash is made from reflective tape unlike other retractable leads which are often made from cord, so it offers higher visibility and is less likely to wrap itself around the dog’s legs causing an accident or injury to the dog.