Personalized Smart Biological Engineer Youth T-Shirt. Biological engineering, the profession for intelligent people text with the letter E in the engineering wearing a hard hat is a funny design with attitude for engineers and college students at back to school, birthdays, holidays and graduation. Let the good times roll in a durable T-Shirt that takes kids from school to play in an amazing array of colors. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar.