Personalized Smart Mechanical Engineer Toddler 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. A toddler-soft cotton tee in look-at-me, big kid colors. 4.5 oz., 100% combed ringspun cotton. White is sewn with 100% cotton thread. Topstitched rib crew neck. Double-needle stitched sleeves and bottom hem. Shoulder-to-shoulder taping.