Under Armour Boys UPF Tank Top (Big Kids) 100% Polyester Imported Machine Wash 30+ UPF protects your skin from the sun's harmful rays. Moisture Transport System wicks sweat away from the body. Print that shows up when exposed to moistureshowing em whos working hardest out there. Smooth HeatGear fabric for comfort & durability on the field. Moisture Transport System wicks sweat away from the body.