Made of PTT, a type of polyester fiber, Rebound™ fabric provides a soft and stretchy texture with gentle cushioning and vivid colors. Its helical molecular structure has a natural resistance to water, coffee, wine, and dirt. It also makes them more comfortable to wear and use. Best of all, they're easy to stretch out so you'll feel confident making riskier moves without any blowouts. Once you pop out of your squat, they'll recover to their original shape without bagging out. Amazing.