Looking for the perfect combination of feel and power? Wilson NXT Power Tennis String (formerly NXT Tour) has you covered. It features high crystallinity Xycro Micro Fibers -- in other words, the string is processed to promote explosive feel on contact. In addition, it helps to increase the sweetspot size and reduce vibration for greater arm comfort. The multifilament construction is coated with a polyurethane resin coating to seal the delicate fibers to enhance durability. The resin material also helps to soften the feel of the string, providing comfort and power. This is a great string to try for anyone with tennis elbow, as well as anyone seeking natural gut like performance from a synthetic construction. Construction: Multifilament polyamide Color: Natural Gauge: 16G, 17G, 18G Length: 40 ft. set   Features: -Comfort -Power -Arm Friendly, for tennis elbow relief