This is lemon-flavored air-flow polishing powder. Polishing makes your teeth smooth and easily removes stains. It is unopened. The recommended use-by date is May 2, 2024. (I am also selling items with a recommended use-by date of October 31, 2024. Please take a look.) I am selling this because the air-flow machine broke and I no longer use it. When you shake the bottle, you can hear a rustling sound. If you purchase multiple items, a small discount is possible, so please inquire. No claims and no returns, please.