The Philips Sonicare Premium Gum Care brush head gives you healthier gums for a healthier smile. Designed to work with all snap-on Sonicare models, these replacement brush heads have flexing sides that contour to your teeth and gums for 2X more surface contact to effortlessly remove your hard-to-reach plaque. Use with a Philips Sonicare BrushSync(TM) compatible handle (DiamondClean Smart or ProtectiveClean) to unlock Smart features: BrushSync mode-pairing triggers your handle to select optimal mode and intensity level for exceptional plaque removal (certain models only) BrushSync replacement technology tracks how often and how hard you brush and will notify you when it is time to replace your brush head. Also, reminder bristles fade to let you know when it's time for replacement. Replace your brush head every 3 months as recommended by the American Dental Association. A fresh brush head every 3 months maximizes the effectiveness of Philips unique Sonicare technology. Essential Oil Warning: Toothpaste containing essential oils can damage your brush head. Avoid direct contact with products that contain essential oils or coconut oil. Use may result in bristle tufts dislodging.