Main Features:Material: safe silicone, nontoxic and no side effectErgonomic shape, easy to adjust, single-side, protecting upper or lower teethDesigned for protecting your mouth and teeth during boxing, ball game and other furious sportsTips:1. Put the mouthguard into 70 - 80 Deg.C hot water in 20s to soften it.2. Put it in your mouth and bite it for 30s, then soak it in cold water.3. Bite the mouthguard and use your nose to breath for quickly getting used to it while you start to use.Caution:It is a personal dental instrument, please replace the mouthguard regularly, 3 - 4 months suggested.