The Oral-B Precision Clean replacement brush head with bacteria protection bristles prevents bacterial growth on the bristles and removes up to 5x more plaque along the gum line than a conventional manual toothbrush. The special bacteria protection bristles help keep your brush head clean. The bristles contain silver-zinc zeolite to inhibit bacterial growth on the brush. They do not have antibacterial effects in the mouth and do not protect against diseases. The blue indicator bristles signal when you should replace the brush head. The replacement brush head is compatible with all Oral-B electric toothbrushes, except for Oral-B Pulsonic. The package includes 8 Oral-B Precision Clean replacement brush heads with bacteria protection.