Keep a nice smile! A good mouth guard fit is important. The gum shield provides protection against strikes landing on the jaw. It protects teeth, lips, and jaw from injuries. A good shield will provide air flow for breathing and stabilize the lower jaw. Please, observe the differences in size for adults and children. In order to get used to wearing the mouthpiece we recommend you wearing it during your entire workout. They are easy to fit and use within a few minutes. Manuals are provided.