NEW for 2017 - 18. The favorite amongst our participants in back and in a great new and bold design. The side paneling features a new material that is softer and more forgiving allowing the piece to move with you. 100% polyester, this piece is very light weight and moisture wicking giving it the ability to be your cooler weather running top. Whether you use it for exercising or out-and-about, this piece will be one of your favorites.