They remove 14 years of teeth stains for a brilliantly whiter smile. Crest 3D White Whitestrips Professional Effects are like an eraser for your teeth. You'll see a whiter smile after 3 days, and full results in 20 days. Their 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. Our exclusive FlexFit technology allows these strips to stretch, covering 30% more of your smile* Achieve professional level teeth whitening results without the professional price tag. *vs. a non-flexing strip