Wilson NXT Power 16 Tennis String NXT Power features high crystallinity Xycro Micro-Fibers bonded with polyurethane for an ideal combination of durability and explosive power upon contact. Originally labeled NXT Tour, this string's softness and comfort are about as close as it comes to natural gut. NXT Power features a 15% larger sweet spot and 80% less vibration than traditional synthetic gut string. Wilson NXT Power 17 Tennis String | Christy Sports