Personalized Mechanical Eggineer Youth Long Sleeve T-Shirt. Eggineers are engineering eggheads and this egg with gears in hand and on it's hard hat with mechanical eggineer text, is a humorous design to tickle your mechanical engineer's funny bone at birthdays, holidays and graduation. youth long sleeve t-shirt. Shoulder-to-shoulder taping. Youth: S(6/8), M(10/12), L(14/16), XL(18/20)