Nuts for Knots Rope Tug with Tennis Ball will literally have your dog going 'nuts for knots'. The tough, durable cotton rope has a loop on one end with a knot and tennis ball on the other. This interactive toy is designed for the active chewer. Play tug-of-war or toss it. It will keep your dog entertained for hours. The Nuts for Knots Rope Tug with Tennis Ball comes in various colors.