Ball's Diameter: 4cm Quantity: 12pcs Features: Simulates the flight of a real golf ball Practice anywhere without worrying about breaking something with these foam balls. This ball is used for indoor practice You can practice an approach shot and full shot. It is safe when hit the furniture, glass window and even person!! but please kindly note it cannot fly far away because it is light - weight ,the longest distance is 10~12m Swing Problems Can be Magnified Practice balls travel less distance than normal balls, but they still mimic the flight of a regular ball. This applies to both foam and plastic practice balls. If you are hooking or slicing a shot, then it will be more noticeable. It is also easy to see if the ball went straight or flew to the left or right. This is one of the main advantages of using practice balls -- plus the fact that you don't have to walk hundreds of yards to pick the balls up. Attetion: