Want to whiten your teeth at home? Crest 3DWhitestrips Professional Effects is designed to whiten like a professional-level teeth whitening treatment at-home. The Advanced Seal Technology's comfortable, no-slip grip means the strips stay put until you take them off, allowing you to talk and even drink water while whitening your teeth. Made by the #1 dentist-recommended at-home teeth whitening brand, Crest 3DWhitestrips Professional Effects will give you a 100% noticeably whiter smile. This enamel-safe, at-home teeth whitening kit will make your teeth 18 levels whiter. Simply apply Crest 3DWhitestrips Professional Effects for 45 minutes a day for 20 days. This pack includes 40 teeth whitening strips, 20 for your top teeth and 20 for your bottom teeth, to be used over the course of 20 days.