Opalescence Quick PF 45% Mint Refill Kit, 1.2 mL Syringe, 40/Pk. contains PF (potassium nitrate and fluoride). 20% water content helps prevent dehydration and shade relapse. Convenient delivery for easy application. Sticky, viscous gel won't migrate to soft tissues and ensures tray stays securely in place. No gingival protection required. For best results, use in a custom scalloped tray. Wear time: 15 to 30 minutes. Vegan, gluten free, kosher. Packaged in 20 blister packs with 2 syringes each.