Indicator bristles signal time to replace brush head. Dentists recommend changing your brush every 3 months. Interchangeable brush head: Floss Action, Pro White, Precision Clean, Sensitive Gum Care, Dual Clean. Does not fit: Vitality Sonic, Sonic Complete, Pulsonic, CrossAction Power. #1 Dentist Recommended Toothbrush Brand Worldwide, Oral-B. Oral-B & Indicator are Trademarks of Procter & Gamble. Braun is a Registered Trademark of Braun, GMBH Kronberg/TS., Germany.