These are a great dishes for feeding roaches and worms to your bearded dragon or other lizard. It can also be used as a water dish as it helps to prevent spills.These bowls are constructed with flat bottoms and are disposable and recycleable, but can be sanitized and reused. The snap-on lids (rings) are constructed with the centers missing to to prevent the insects from escaping while allowing access to the insects. The Small dish is 3 1/2" in dia. and has an opening of 2 1/2" which is appropriate for young bearded dragons, geckos, and other small lizards. The large dish is 5" in dia. and has an opening of 3 1/2" which is appropriate for older bearded dragons and other animals.