Mouth Guard for Grinding Teeth, Night Guard, Moldable Dental Guard, Professional Mouth Grinding Guard, Comfortable Custom Mold for Clenching, Bruxism, Whitening Tray & Sports Guard (4 Pack, 2 Sizes).This is a set of 4 mouthguards, I like that there are 2 sizes available in this box.I mainly got it for smaller size for my kid who grinds at night.Its really hard to find smaller size mothguards anywhere with good quality.I like these as these are good quality and dos help my child while he is sleeping and prevents him from grinding.