Personalized Smart Mechanical Engineer T-Shirt. Mechanical engineering, the profession for intelligent people text with the E in engineering wearing a hard hat, is a humorous design with attitude for college students and engineers at back to school, birthdays, holidays and graduation. 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.