NEW for 2017 - 18. The favorite amongst our female 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.