Opalescence Go take-home whitening system is recommended for patients looking for professional whitening to go or as an alternative to over-the-counter whitening products. With no impressions, models, or lab time required, Opalescence Go whitening trays are also a perfect follow-up to in-office whitening. 6% hydrogen peroxide. Contains PF (potassium nitrate and fluoride). Wear 60-90min for 5-10 days. Mint flavor. Stored in the fridge. Contains 4 sets of trays (4 x upper and 4 x lower trays in each kit).