Gentle yet effective cleaning of sensitive teeth and gums: these electric toothbrush heads feature a unique design with long, thin, ultra-soft bristles that keep every brush stroke kind Remove up to 1000% more plaque than a manual toothbrush in hard-to-reach areas with more than 3,000 densely packed bristles designed to provide thorough yet gentle brushing Proven Sonicare technology: deep and gentle cleaning with up to 62,000 bristle movements; Sonicare Fluid Action supports cleaning by driving fluid deep between teeth and along the gumline BrushSync replacement reminder⁵ 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