42 strips: 21 treatments (Each with 1 upper/1 lower). Levels 24 whiter. Professional level whitening removes over 25 years of stains. No slip technology. Enamel safe. Crest 3D Whitestrips use the same whitening ingredient as dentists. Peroxide layer. With a comfortable, no slip whitening experience. No. 1 dentist recommend at-home whitening brand. Anti-theft program. 100% Satisfaction Guaranteed: Satisfaction Guaranteed: Crest 3D Whitestrips provide you with a beautiful, whiter smile - guaranteed. If you are not satisfied with your results, Crest will send you a pre-paid card in the amount of your purchase. Simply return your receipt and package UPC within 60 days of purchase. Limit to one refund per person. Call 1-800-208-0169 for more information. www.pg.com. www.crest.com/whitestrips. To learn more about Crest 3D Whitestrips go to crestwhitesmile.com. Questions? 1-800-395-8423.