Bite down on a cheap jaw ball and you're biting into empty space — hollow rubber that gives way before your jaw even starts working. Bite down on JawFlex and you're pushing against solid material the whole way, so your jaw actually works instead of just moving.
Bite a round ball and it slides toward your front teeth — so you tire out the wrong muscle and skip the one that actually shapes your jawline. Bite JawFlex and it sits right on your back molars, exactly where your jawline gets built.

