The iO 3 electric toothbrush incorporates Oral-B's best technology, combining a round brush head inspired by professional toothbrushes with micro-vibrating bristles to deliver a professional-level clean at home. The intelligent pressure sensor prevents you from brushing too hard or too softly to better protect your gums. Gum Guard alerts you when you brush with too much pressure. Replace your Oral-B iO toothbrush head every 3 months for best results.