This is an ultralight mouth guard made from a high-tech thermoplastic material. The 2.4 refers to the thickness of the mouth guard. The 1.6mm is slightly thinner, and this 2.4 is thicker and provides more protection. Compared to a conventional mouth guard it provides 50% better protection than a standard mouth guard. These mouth guards fit snug to your teeth ensuring a perfect custom fit. Best of all you can easily breathe, talk and drink with the mouth guard in. No more picking up your mouth guard off the ground after it falls out. Perfect for any spot such as Basketball, Soccer, Lacrosse, Hockey, and Roller Derby, where communication, comfort, and protection are key. These mouth guards were created by Dr. Jan Akervall, MD, PhD, and a top 1% ENT Doctor in the U.S.