“Flexi dog leads” is the name given to extendable dog leads by their inventor and manufacturer, Flexi.   These dog leads are different from other dog leads because they are extendable and the braking system is ergonomically designed to be operated with one hand with little recoil.  The leash runs smoothly in and out on an internal spring, which also keeps the lead under a slight amount of tension.

There are three types of “Flexi dog leads”, one for smaller dogs and two others for larger dogs.  The lead for a smaller dog is a cord that fastens to the dog's collar.  The leads for larger dogs are made either out of tape or out of a belt to enable better control of a dog.  “Flexi dog leads” are not meant to be used on uncontrollable dogs or on dogs, which are disobedient, as they are potentially harmful to people in those situations. 

What harm can “Flexi dog leads” do?  The least harmful thing it can do is cause burns similar to rope burns if the purchaser allows their dog to pull the leash at a rapid pace across any part of their body.  If the lead becomes tangled with or wrapped around any part of the person's body, like their hands or fingers, the dog can potentially jerk it hard enough to either break or amputate that part.  Additionally, if the leash breaks, or if the dog's collar breaks, and there is enough tension on the lead, the leash can snap back and hit the person walking the dog in the face, causing potentially serious injuries such as eye injuries, bruises, or even broken teeth.

Another serious type of damage that can be caused by  “Flexi dog leads” are those injuries commonly caused by falls.  To prevent this, keep the dog on a short leash by only extending the dog lead partially and putting the brake on.  This will prevent the dog from building up enough momentum to pull the handler to the ground.  Another thing to be aware of it that, unlike the situation with a regular dog lead, “Flexi dog leads” are long enough to potentially be wrapped around a bystander, with the attendant risk of injury to a bystander.  This means that the handler needs to be aware of any bystanders in the area and take steps to make sure the bystander is not wrapped in the leash.