Personalized Ruler T-Shirt. I am the ruler text with a ruler replacing the letter L in ruler is a humorous gift design for back to school, birthdays and holidays. 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.