Philips Sonicare Teeth Whitening Gel Refills (Caring) are used with Philips Sonicare moldable whitening trays as part of a teeth whitening kit. Whiten your teeth at home with ease! The refill package contains 3 dual-barrel syringes (2.4 ml each) with 3 doses of the hydrogen peroxide whitening gel (6% hydrogen peroxide) in each applicator. The dentist-developed gel is designed for maximum comfort: proven safe on enamel and gentle on teeth. Dispense using the dual syringe applicator. A droplet size indicator on the side helps you use the right amount of gel each time. Philips Sonicare's whitening gel is clinically trialed and tested by users who reported little or no tooth sensitivity³. Fast and effective, visible results can be seen in 3 days¹. A standard course of treatment is 9 consecutive days. Each Philips Sonicare dental whitening kit contains 9 treatments of Philips Sonicare's innovative gel. ¹ 67% of 63 participants, US, 2022 ² 85% of 60 participants agreed, US, 2022 ³ 81% of 67 participants, US, 2022 ⁴ 82% of 60 participants agree, US, 2022