We make our black, 13" ball bungee straps from two heavy-duty elastic bands secured by a single ball. Ball bungees are excellent for connecting your tarp to the framework and roof of your canopy structure for a strong and sturdy fit. At Canopies and Tarps, your canopy structure's needs are our specialty! 1/5-inch cord diameter (5mm), relaxed length including ball is 13-inches, Stretched length is 17.5 inches