The Oral-B CrossAction Replacement Electric Toothbrush Head is Oral-B's most advanced technology. It features perfectly angled bristles to remove 500% more plaque for a superior clean**. The round brush head is inspired by dental professional tools for a tooth-by-tooth clean, with specially engineered bristles. Additionally, the Bacteria Guard Bristles help keep your brush clean for up to 3 months*. *inhibits microbial growth that may affect the bristles. The bristles do not kill bacteria in the mouth or protect you against disease. Always clean the product thoroughly after use. **vs. a regular manual toothbrush when used on Pro 1000 and up handles