Personalized TA Lab Rat Long Sleeve T-Shirt. TA lab rat text is a humorous gift design for teaching assistants at back to school, birthdays and holidays. 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