What retailers sell tennis ball launchers?

If you are looking for the type of tennis ball launcher that dog owners use to avoid touching a drooly tennis ball, those are available for sale at all pet stores, and usually in the pet 'section' of most department stores. If you are looking for the type of machine that launches tennis balls at tennis players to help them improve their tennis skills, than the Silent Partner is a great company to order from. They are a Canadian company, but they have a warehouse in the U.S. to serve the tennis market as well.