Opalescence Go Prefilled Whitening Trays, Mint 15%, 4/Kit, Case of 12 Mini Kits. Contains 4 single-use blister packs with 1 upper and 1 lower tray. Wearing time: 15-20 minutes for 5-10 days. Contains PF (potassium nitrate and fluoride). No impressions or custom trays necessary, ready to use right out of the package. Vegan, no animal products. Certified gluten-free and kosher. Case of 12 mini kits