The AFP Automatic Ball Launcher Dog Ball Thrower Machine Hyper Fetch Tennis Ball Dog Ball Launcher(Maxi) (Maxi-New) is a great way to exercise your dog and train them to be more active. With its adjustable distance setting, it can be used to throw the ball 10 feet, 20 feet, or 30 feet away. The machine also includes three standard tennis balls so you can have a game of fetch with your dog. It works with six pcs C batteries (not included) or with an AC adapter (included).