GoSmile really nailed it with this teeth whitening system. The ampules are tiny and fit into any purse. Its easy to apply and you never have to deal with a sticky mess. I am very happy that this product exists in the market. When I first tried it I accidentally missed a spot and you could see the difference! It was amazing. Of course with any topical teeth whitening, it won't sensitize your teeth and the best part of this product that sets them apart is that it freshens your breath as well. The B1 system is used 14 days straight and not more than three times a year. Too much whitening is not good for your teeth.