Personalized I Believe In Santa 2 Long Sleeve T-Shirt. Funny Christmas Long Sleeve T-Shirt - Pink with Santa cap says I BELIEVE IN SANTA... JUST BECLAUS. Perfect holiday gift for anyone who believes in Santa Claus and Christmas. Pre-shrunk 100% cotton 6.1 ounce long sleeve t-shirt. Double-needle stitched neckline and sleeves. Quarter turned. Shoulder-to-shoulder taping. Adult: S, M, L, XL, 2XL, 3XL