The EvoShield® Baseball Catcher's Thumb Guard was designed by Pro Athletic Trainers and is the only MLB®-approved baseball thumb guard. This thumb guard for catchers fits comfortably inside your glove to help brace and protect your thumb from impact. Built to disperse, not absorb, this EvoShield® guard uses air-activation technology to custom-mold to your thumb and provide a soft and flexible shield. FEATURES: Baseball and softball catcher's thumb guard Designed by the nation’s top Professional Athletic Trainers Only MLB® authentic baseball thumb guard Air-activated custom molding process provides the ultimate thumb protection Fits comfortably inside your catcher's glove to protect you from a jammed thumb Prevents thumb and ulnar collateral ligament injuries Gel-to-Shell™ technology rapidly evolves the soft gel pad into a protective shield Size: small (youth) = 4.25" x 3.5" Size: large (adult) = 4.5" x 4.5" Care: hand washable and air dry Model: A130 EvoShield WARNING: It is advised that you DO NOT open the foil packaging until you are ready to use. The product will turn into a hard protective shell within minutes of being opened and cannot be restored to its original state.