How does the Pressure Sensor Feedback work on my Philips Sonicare?
You Sonicare toothbrush measures the pressure you apply while brushing to protect your gums and teeth from damage. If you apply excess pressure, the handle will change its vibration and the brushing feedback light at the base of the toothbrush will flash purple until you reduce the pressure.
Note: The Sonicare 9900 Prestige comes with this feature already activated. To deactivate this feature, go to the user manual and see the section 'Activating or deactivating features'.