The Oral-B iO Series 3 electric toothbrush features Oral-B's best technology, combining a dentist-inspired round brush head with micro-vibrating bristles for a professional purifying clean feel at home. The Smart Pressure Sensor helps prevent you from brushing either too hard or too softly to better protect your gums. Replace your Oral-B iO Brush Head every 3 months for best results Oral-B's revolutionary iO technology delivers a professional, purifying clean feeling every day 3 Smart Modes to personalize your brushing: Daily Clean, Whitening, Sensitive Combines Oral-B's iconic dentist-inspired round brush head with gentle micro-vibrations to remove harmful bacterial plaque Smart Pressure Sensor signals red, white or green to alert you if you're brushing too hard, too softly or with just the right pressure. Smart Ring flashes a 360 ring of colors to celebrate completion of a dentist-recommended 2 minutes of brushing iO's smart tracker reminds you when the brush head needs to be changed with a yellow LED light, to keep your clean at its best.