Crossing the springs of a trampoline increases the surface tension of the mat. Crossed springs rub against each other and, as a result, wear out faster. This leads to a loosening of the tension in both the springs and the mat, ultimately affecting the trampoline's performance. With the Acon X, you can increase the surface tension without crossing the springs by adding more springs using the Acon X Performance Spring Kit. The Acon X 17 Trampoline was designed to allow jumpers more ways to customize their spring setups in order to create the perfect bounce for you.