ightweight feel, for a flexible type of user Relying on advanced computing system, so that film frame to achieve low drag. High strength, and to meet the needs of the different style of play. Can provide consistent with the different players racket, because the aerodynamic design based. Measured by mass, for different play features. LI NING WINDSTORM 660 FEATURES: “M”PCF(Multi-Layered Polymer Carbon Fibers): Reinforcing Technology Handcrafted multi-layered carbon producing multi-directional strength. Provides strength & durability at key stress points. “H”DF (High Density Foam) : Shock Absorption High tech and light weight shock absorption materials fill racket head cavities Lightweight, high-tech shock absorption materials within racquet frames that minimizes arm strain at impact. “U”HB (Ultrafine High Tensile Biometric): High Flex Point Racket shaft flexes closer to the racket head to produce improved smash and drop shot performance. With an optimized shaft performance, this technology provides low wind resistance with high-flexibility & strength for superior smashing! TB.NANO (TB Nano Powertec) : Nanometer Technology Enhanced nano technology bonds carbon fibres to resin to increase the raw material strength by 20% Original Li-Ning TB Nano Material Science and Technology creates a more stable and finer racket. More Powerful “sweet spot”. WING STABILIZER: Aviation Technology with Introducing aviation Technology design that releases the metal performance memory and improves control an strokes. The inter-field application of aviation technology on Li-Ning products. The frame from 3 & 9 o’clock zones made of ultra elastic 3G titanium alloy, which resists shake and vibration. The distinguished feature of metal memory will control the frame restoration precisely at the moment of deformation and to restrain the shake resulting from vibration waves. The anti-tarsion performance of strokes is improved under high tension conditions and brings about a quick exact and stable second stroke. 3D BRAID POWERTEC: Continuous multi-layer and multi-dimensional carbon fiber weaving method. Seamless, light, rigid & durable. HIGH TENSILE SLIM SHAFT: Engineered with variable shaft diameters. Allows for greater torsion to enhance hitting power while releasing frame to restore more quickly. TI TANIUM EXTRA ELASTIC TECHNOLOGY: on core aviation principles, anti deformation and increased stability of frame. TAPER SHAFT: Engineered with variable shaft diameters: wider at the bottom and tapered at the top. Allows for greater torsion to enhance hitting power while releasing frame to restore more quickly. ULTRA-CARBON: Made of ultra strong material, the racquet has optimum rigidity to bear higher tension for exact and steady strokes. Made of rigid carbon fibers allowing for higher string tension. Risk of frame deformation is also minimized. AEROTEC-BEAM SYSTEM: Aerodynamic design with low air resistance and high tensile strength. DYNAMIC-OPTIMUM FRAME: Improved racquet mechanical structure for more efficient attack and defense. Increased “sweet spot” for improved hitting velocity with wider string area to increase bounce strength.