You want to let the dog out in the backyard for a little fresh air and sunshine, but he has a bad habit of escaping the yard. There are some dogs that are just expert at finding ways out of the yard when you are not looking. A runner in the yard limits the mobility of the dog and you would rather allow him the freedom to run in the yard the way he chooses. A wireless dog fence might be the answer you are looking for.
A dog that escapes from the yard is a disaster waiting to happen. Even if your dog is the friendliest least aggressive dog on the block, there is no telling what he will do if he becomes frightened. Biting someone that he feels is a threat is a definite possibility for a dog that is wandering the neighborhood on his own. There is also a danger that a car can injure the dog if he wanders into the road during his jaunt down the street. With a wireless dog fence you are protecting the dog as much as you are protecting others from the dog.
The wireless dog fence should be used in conjunction with effective dog training. You must teach your dog where his boundaries are and how to behave in the presence of other dogs and people. It is natural for your dog to want to protect you and their territory, but they must learn that aggressive behavior will not be tolerated by you and that you are the one that is in charge. Dogs operate with a pack mentality and you must establish yourself as the leader of his pack for him to respect your authority.
A wireless dog fence will give the dog reminders about the boundaries that you have set. It is completely harmless to the dog and will not hurt him in any way. But it will deliver a clear message that he has overstepped his boundaries. Once a dog has received the message often enough, he will begin to understand what he is and is not allowed to do. It will take consistent training on your part in addition to the wireless dog fence.
Look into all of your dog training options and be a responsible dog owner by making sure that your dog is contained in your yard. You will be protecting him from all sorts of trouble as well as protecting your neighbors from your dog. You have a commitment to take care of this animal and making sure he stays safe is your top priority.