Really, this question is a good one for any dog. First, you will want to know how much your dog weighs. In the case of a Labrador, they can weigh anywhere from 55 to 79-pounds so you will want to pick one that can appropriately hold the weight of your dog. You will also need to keep in mind that if your dog is a puller, you will want one tough enough to tolerate the pulling. The length of the leash will also depend on how much freedom you want to give to your dog.