When you purchase the SplinTrex 3-in-1 Mouth Guard 4 PACK with carrying case you will receive 4 high quality mouth guards that can be used for either Nighttime Teeth Grinding Protection, as an Athletic Mouth Guard or as a Teeth Whitening Tray. QUALITY - SplinTrex Mouth Guards are made with high quality material that is BPA Free. 100% Satisfaction is GUARANTEED. - PERFECT FIT - easily trimmed to fit any mouth size (even the smallest mouth) - PROFESSIONALLY DESIGNED - slim and flexible design so you can sleep comfortably - CUSTOM MOLDED - you can custom mold your mouth guard to ensure a precise fit - this is not a one size fits all mouth guard! Plus get a Free Replacement if you mismold - BUILT TO LAST - thick 3mm durable base provides extra cushion and shock absorption and also prevents wear through - EASILY ADAPTED - Fits a variety of teeth alignments, tooth size & mouth shape for optimal retention - secure fit locks in place while sleeping or using as an athletic mouth guard. Can be worn on either upper or lower teeth -Try our SplinTrex 3-in-1 Mouth Guards for 30 days. If you don't love the way they fit or work for you, we'll give you your full payment back no questions asked, whether you use 1 or all 3 mouth guards in the set.