Personalized I Believe In Santa Youth T-Shirt. Cute Christmas Youth T-Shirt - White with Santa Claus cap says I BELIEVE IN SANTA JUST BECLAUSE. For anyone who still believes, just because. Let the good times roll in a durable T-Shirt that takes kids from school to play in an amazing array of colors. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar.