Personalized Keep Calm Cinco De Mayo Long Sleeve T-Shirt. Cinco De Mayo Long Sleeve T-Shirt - White with colorful fiesta sombrero and KEEP CALM IT'S CINCO DE MAYO saying. 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