Achieve up to 7x healthier gums in just 2 weeks¹: this brush head's concave bristle layout allows the outer bristles to keep your gum line brushed even while you're focusing on your teeth Remove up to 1000% more plaque¹ in hard-to-reach areas with engineered flexibility: the soft-touch rubber head enhances bristle motion for increased coverage and more thorough cleaning Proven Sonicare technology cleans gently yet effectively with up to 62,000 bristle movements; Sonicare Fluid Action supports cleaning by driving fluid deep between teeth and along the gumline BrushSync replacement reminder⁶ tracks how often and how hard you brush; the light on the handle will turn on when it's time to replace your brush head, blue bristles will also turn white These sonic toothbrush replacement heads are compatible with all Philips Sonicare click-on electric toothbrushes⁴: simply click one on or off for easy replacement and cleaning Philips aims to reduce the use of fossil fuel-based plastic, that's why 70% of the plastic in these sonic toothbrush replacement heads is bio-based²; paper-based recyclable packaging³