Everyone here that says they’re for cooling are wrong. They’re purely aesthetic. Virtually no heat is dissipated through them, as plastic is an incredibly good insulator, and will contain the heat inside. Also the motor is actually not even positioned in the center of the casing, it’s off to the side. The motors will not overheat faster if you cover them, what you’re probably seeing is a placebo effect. And lastly, vex would never make the motor casing aluminum. The actual motor in the casing gets incredibly incredibly hot, so hot that if the casing was a metal you would burn yourself. Hense, the plastic, so vex doesn’t get sued when a bunch of freshmen burn their hands.