Specially processed melamine foam for teeth care contains "split polyphosphoric acid," a liquid with a coating effect refined by our proprietary technology.It can be used in places where water is not available.Easy to use, just take out the sponge from the packet and gently scrub the tooth surface.It is very easy to use. It removes stains caused by coffee, cigarettes, red wine, etc., and at the same time coats the tooth surface to make it smooth, making it difficult for stains to adhere to the tooth surface again.This is a revolutionary product that allows anyone to easily care for their teeth "anytime, anywhere, and by anyone" at an affordable price.