These are the metal dots that go on the ball for all the radar based systems such as Flightscope Mevo, Mevo+, X3, XI, XI +, XI Tour, X2, X2 Elite, and all the Trackman systems. The metal dot increases the ability to get an accurate spin reading from the radar unit when using indoors. My dots have been tested time and time again and perform perfectly. These are the ones that are the same thickness as the ones that come with the units and show that in certain environments, these hold up and read vs the thinner ones.