Nuts for Knots 3-Knot Rope with 2 Tennis Balls will literally have your pet going 'nuts for knots'. The tough, durable cotton rope has a knot on each end and one in the middle. In between the knots are 2 tennis balls. Play a game of tug-of-war or toss it around, this interactive toy will keep your pet entertained for hours. Nuts for Knots 3-Knot Rope with 2 Tennis Balls come in various colors.