Heart-Guard Youth Protective Safety Plate (Worn Under Jerseys Virtually Invisible) for Baseball Pitchers, Catchers, Infielders, etc Baseball/Softball Youth Ballplayers Heart-Gard Protection. One size fits all up to 120 lbs. Tough polyethylene dome absorbs impact energy and forces it away from the heart. Small size covers the vital area of the chest, yet does not restrict movement. Improves confidence and playing ability. Heart-Gard is small in size, measuring 6" x 6", yet is the largest rigid plate over the vital area of any protector and does not restrict movement. Kids learn faster and with greater confidence. When worn under the uniform, it is virtually invisible. Cool and lightweight, weighing less than 3 oz., kids forget they are wearing it. Adjustable elastic straps.