Opalescence Boost PF - 40% HP In-Office Power Whitener, Econo Refill: 20 - 1.2 ml Opalescence Boost /Activator syringes. Powerful 40% hydrogen peroxide gel is chemically activated, so it doesn’t require a hot, uncomfortable light to work. Contains PF (Potassium nitrate and Fluoride). Fresh chemical for each application. No refrigeration required prior to mixing. 20 - 1.2 ml syringes