Designed with stability, comfort, and durability in mind, the Head Revolt Pro 4.5 takes what you loved from the previous versions and makes subtle improvements for a great all-around performer. The upper has been reconstructed for a more supportive and locked in fit. Aesthetically, the upper is more technical and clean looking, with a wave-like design that contours nicely to your feet and also allows for ventilation, with a mesh layer underneath. Within the midsole the Tri-Nrg system not only delivers comfort and shock-absorption, but helps to stabilize your feet when pushing off and accelerating. Head's signature Hybrasion rubber has been formulated to withstand the wear and tear while playing on hard courts, but the traction will perform on a variety of court  surfaces. Outsole is backed by a six-month outsole durability guarantee.