This shoe runs large, we recommend sizing down a half size. The GEL-RESOLUTION X tennis shoe creates advanced comfort for players who like to control the game from the baseline. DYNAWALL technology in the midsole now extends into the heel for added stability during lateral movements. It's a functional feature that's effective when you're running covering both sides of the baseline. DYNALACING technology has been strategically designed to hold when extra support is needed. This allows you to experience a locked-in feel when you're making quick transitions. There's also a two-piece midsole design that helps improve stability when your foot lands on the court. Lastly, the higher medial collar helps prevent ankle twisting when making abrupt cuts back and forth. Polyester upper and lining. Ethylene vinyl acetate insole. Two-piece midsole design helps produce more stable landings. DYNAWALL technology helps improve stability. DYNALACING technology helps improve stability during lateral movements. PGUARD technology helps increase durability in the outsole's toe and heel area. AHARPLUS outsole rubber improves durability.