Set of 2 dental mirrors and 2 plaque checkers. How to use the plaque checker: 1. Lightly brush your teeth. 2. Apply the plaque checker to the surface of your teeth with a cotton swab, etc. 3. Rinse your mouth with water. 4. Check your teeth in the mirror and find the red-stained areas (where plaque remains), and brush them with a toothbrush. Even young children can easily see where they've missed brushing, which helps prevent cavities!