Perfect for my 4 year old ninja
My 4 year old moved up to the sparring class this past testing cycle and needed a mouth guard. She has some sensory issues with things in her mouth due to losing her four front top teeth in an accident, but we were able to trim this mouth guard down and shape it to fit appropriately. She now happily wears it for class.  The case and mini carabiner have held up well being clipped onto the top handle of her sparring gear bag.  I still have 5 spares in case we lose one or to pass along to friends in class that struggle with the basic ones our studio gives out.
Rating: 5 stars