Multi-level brisltes for up to 5x better cleaning at the gum line (vs a regular manual toothbrush based on in vitro laboratory testing). Fits most Oral-B electric toothbrushes. See back for compatibility. Multi-level bristle design for more effective cleaning than a manual toothbrush. Light-Blue Replace-Me Bristles fade with use to remind user to replace brush head. Identifier color rings. Compatible with Most Oral-B Electric Toothbrushes. Does not fit Vitality Sonic, Oral-B Sonic Complete, Pulsonic, Crossaction Power Battery Toothbrush, Oral-B Complete Battery Toothbrush, and 3D White Battery Toothbrush (Oral-B, Vitality Crossaction Power, Oral-B Complete Floss Action, 3D White and Pulsonic Are Registered Trademarks of the Procter & Gamble Company or one of its affiliates). 100% Quality Guaranteed: Like it or let us make it right. That's our quality promise.