The Dunlop FX 500 Tour Demo Tennis Racquet is built on the concept of controllable power. 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 grommets 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. The FX 500 Tour is the most stable and control oriented frame in the FX collection. The 98 square inch head and 16x19 string pattern work hand in hand to create a spin friendly and explosive response. While the other FX racquets have a slightly thicker cross section, the FX 500 Tour's 21/23/22 millimeter beam is more nimble and precise. With an unstrung weight of 10.8 ounces, the FX 500 Tour should be maneuverable enough for both intermediate and advanced players. Dunlop brings the power with the new FX 500 Tour, but don't let the 70 flex rating fool you, the brand has packed this model with technology to make the frame very comfortable to play.