Works with Medium chuckit balls. Terrific way to exercise your dog without wearing yourself out! Throw tennis balls 2 or 3 times father with the Original Ball Launcher. Hands-free pick-up - no more slobbery tennis balls. Features an ergonomic handle for the ultimate comfort & control. Made from durable lightweight flexible plastic Comes in a variety of throwing ranges and ball sizes. Use with standard tennis balls or Chuckit!® compatible medium balls only.