The AFP Automatic Ball Launcher for Dogs is an automatic, interactive fetch system that keeps your pet happy while giving your arm a break. The launcher can throw balls to 10 ft (3 m), 20 ft (6 m), or 30 ft (9 m) and comes with 3 pcs of 2/5 cm dog tennis balls. The ball launcher has a tennis ball sensor that will automatically launch balls every 10 seconds. It also includes 6 C batteries and is easy to install and use. Your dog will enjoy a happy time with this tennis ball launcher for dogs.