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. Crest 3DWhitestrips Professional Effects will give you 100% noticeably whiter teeth, guaranteed. Validated by the Canadian Dental Association, this enamel-safe, at-home teeth whitening kit removes over 15 years of stains in 3 days. Simply apply Crest 3DWhitestrips Professional Effects for 30 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.