The Heart-Gard is a tough, high-density polyethylene dome that absorbs impact energy and forces it away from the heart. The small size covers the vital area of the chest, yet does not restrict movement. Small in size, measuring 6" x 6", yet is the largest rigid plate over the vital area of any protector and when worn under the uniform, it is virtually invisible. The Heart-Gard is so lightweight; kids forget they are wearing it. Heart-Gard is designed to reduce ball impact to areas covered by the device and should reduce the risk of injury, but will not necessarily prevent all injuries.