SMILE IN COLOR IS A TOOTH PIGMENT, THAT IS SAFE FOR TEETH, OUR "PERFECT WHITE" COLOR HAS BEEN FEATURED AND IS USED BY MODELS AND INFLUENCERS. IT IS VERY EASY TO APPLY, SHAKE BOTTLE, USE THE BRUSH TO BRUSH IT ON YOUR TEETH AND LET DRY FOR 10-15 SECONDS, IT CAN LASTS FOR UP TO 24 HOURS AT A TIME.