Personalized Happy Birthday with Dog and Mouse Long Sleeve T-Shirt. Dog and Mouse are excited to wish you the happiest of birthdays! Happy Birthday with Dog and Mouse Long Sleeve T-Shirt - White, perfect for those who love this friendly duo from "Dog and Mouse" by Michelle Nelson-Schmidt. 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