Personalized Mouse T-Shirt. A great finder, a great helper, and a great friend. Mouse T-Shirt - Athletic Heather from "Dog and Mouse" by Michelle Nelson-Schmidt wants to help, not because she has to, but because she wants to. Everyone loves our Custom T-Shirts! Wardrobe essential for looking good, 24/7. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar. Shoulder-to-shoulder taping. Double-needle stitched sleeves, bottom hem and front neck. Note: greys are a cotton/polyester blend.