The Dunlop FX 500 LS Tennis Racquet offers the latest game improvement technology in much easier to manage weight. Dunlop's Sonic Core technology with Infinergy returns in the FX series. The elastic foam material produces a more dampened and comfortable response during contact. The "F" in FX refers to "Force" and it includes a few new game improvement innovations. The entire hoop incorporates a new Power Boost Groove under the grommet strip to elongate string movement and simultaneously create more power and comfort. The FX series features a new Aerodynamic Power head shape for improved mobility, and a wider throat section with improved stability. To make sure the power focused FX racquets remain comfortable, a unique high performance thermoplastic elastomer compound called Flex Touch Resin is built into the shaft. The material provides greater rebound off the string bed and improved vibration dampening when compared with a traditional graphite construction.