Evoshield Women's Racerback Chest and Back Guard Comfortable heart protector features Shields that truly custom-mold to each athlete for greater confidence at the plate or on the mound. Extended coverage area of Shields offers additional protection to key vulnerable areas on the side and back. Most chest protectors only cover a small area over the chest/heart. Does not limit mobility or interfere with throwing motion in any way. Comfortable, sweat-wicking performance fabric. Gel-to-Shell technology disperses impact, rather than absorbing, for stronger protection than traditional foams and plastic. Sizing based on chest measurement at widest point: SM 33-35; MD 35-37.5; LG 37.5-40.5; XL 40.5-43.5; 2XL 43.5-48.5 Air Activated: Easty to Use - Simply rip open the foil pouch to activate the molding process. The chemical components inside the soft pads react to moisture in the air, activating the hardening process. Custom-Molding: Perfect Fit - Once activated, the soft pads transform to hard and protective, custom molding to the exact contours of each individual athlete. Ultrathin, Lightweight: Fast, Agile - At just 1/4 of an inch thin, EvoShield's protctive Shields are designed to act as a second skin with a unique protctive barrier. Athletic Design: Quick, Confident - EvoShield was developed under the direct specifications of elite athletes, ensuring a custom fit that never interferes with the body's natural movement. Breathable: Comfortable - EvoShield's protective Shields are encased within a breathable mesh layer that comfortably hugs the body.