If you're looking for an optimal playing string that provides superior shock absorption and gut-like playability, then look no further than Wilson NXT 17 tennis string. This string replaces Sensation NXT 17 but provides the same great performance with a new name. You'll experience comfort, feel and great playability. Wilson's premier playability string. Constructed with polyurethane, the same material used for cushioning in your shoes, so this string is a great choice even if you suffer from arm pain. Closest playing string to natural gut, No.1 rated synthetic gut string for playability and comfort (USRSA). Expands sweetspot by 10% and reduces vibration up to 74% vs. traditional synthetic gut. Composition: 680 Xycro Micro Fibers impregnated with 32% polyurethane, patented construction.