The Philips Sonicare Optimal Plaque Control brush head features a concave trim profile specifically designed to target tooth-decaying plaque by hugging teeth and offering better conformity and surface-area coverage. Compatible with all click-on Sonicare models, these replacement brush heads remove up to 6x more plaque than a manual toothbrush. 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.