Champion Women's Action Tech Sports Bra Body: 76% Tactel Nylon, 24% Spandex; Mesh inserts: 67% Nylon, 33% Spandex sports-bras closure Cotton-blend fabric feels super-soft yet withstands your toughest workouts. (Helps manage moisture, too.) Knit-in four-way stretch controls bounce, gives superb support. Inner lining wicks away sweat to keep you fresh and dry. Ribbed, channeled bottom band adds cooling ventilation. Stay-put racer-back straps lend support plus allow free movement. No hardware to chafe or dig! Tag-free pullover styling, with keyhole back for extra cool. A Classic Compression sports bra. Body fabric: cotton/polyester/spandex. (Birch Heather body fabric is cotton/spandex.) Lining: polyester/spandex