These Philips Sonicare brush heads fit the natural shape of your teeth for a thorough clean. The brush heads feature reminder bristles that fade when replacement is needed. For best results use only Philips Sonicare brush heads. Philips recommends replacing your brush head every 3 months for optimal results. These e series brush heads fit: Philips Sonicare Advance, CleanCare, Elite, Essence, and Xtreme power toothbrushes.