Young puppies should be fitted with a plain, soft collar and a lead of average length (about 4-6 ft). A lead and collar of a sturdy but light material (such as nylon) usually work well to start. These are good tools to use while your puppy is learning to walk with you. Avoid anything too heavy while your puppy is getting used to the feel of a collar and lead.
As your puppy grows, there are a variety of tools to help with training. Extra long leads (about 15 ft) can be helpful for keeping your dog safe and attached to you while still allowing enough extra space for you to begin teaching the "come" command.
stay in control
When a dog pulls hard against a collar, there is lot of pressure against the trachea (windpipe). A harness distributes the pressure over the chest, instead. Harnesses can be helpful for dogs with neck or spinal problems, or for dogs with a condition called collapsing trachea. We also recommend harnesses for dogs who pull so hard that they cough or gag.