The Oral-B Precision Clean replacement toothbrush head provides up to 400% more plaque removal along the gum line*. The round brush head is inspired by dental professional tools for a tooth-by-tooth clean, with specially engineered bristles. The Oral-B Precision Clean toothbrush head features Max Clean Bristle Technology which signals when to change brush head to maximize your clean. Green bristles turn yellow when it's time to replace brush head. *vs. a regular manual toothbrush