I bought this when i had my German Shepherd puppy, she was already pulling hard on the lead at 5 months, so in order to get used properly to the lead, i purchased one of these to help the training. It is handy, as you can have it at whatever length you like and it will remain there. The longest is 5m, but the catch dosn't always hold the lead, it takes one strong pull and it will tend to extend when you don't want it to. One not very pleasant example is if you are walking your dog where you don't want it to and they have the urge to take off, the lead will then unlock and you are pulled with it. But if you have a dog who is gentle and not prone to pulling on a lead, then this is ideal. The dog will have the freedom of not being restricted by walking next to you, but they are being controlled by being on a lead.