The Dura Outdoor Pickleballs, also known as the Dura Fast 40, are a seamless plastic whiffle ball specially designed for pickleball. They, like all outdoor pickleballs, have thick walls. The purpose of using hard plastic for a pickleball is to increase the life span of the ball in rough outdoor conditions. The name of the ball is short for "durable" and these balls live up to their name. The ball is made by injecting a single glob of hot plastic into a mold. The mold is closed and rotated to spread the plastic evenly around the walls of the mold. When the mold has stopped spinning it is opened and the new ball is removed from the mold. Sometimes there is a minor separation seam from excess plastic that leaked out of the mold. This excess plastic is sanded off. Look inside the ball and you will not see a seam. There are two sizes of holes drilled into this ball. The two sizes of holes and the hole configuration, help make the ball more aerodynamic. The Dura Outdoor Pickleballs is a heavy ball, weighing 0.92 ounces. This weight helps keep the ball flying straight even in windy conditions. The weight also makes them a fast ball, compared to the softer and lighter Jugs Indoor Pickleball. The Dura are also a rather big, the ball measures 2.9375" in diameter. The ball has an average bounce height of 32", promising lively response to every hit.