The iO 4 electric toothbrush features Oral-B's best technology, combining a dentist-inspired round head with micro-vibration fibers for a professional feel of thorough cleaning at home. The Smart Pressure Sensor helps you brush neither too hard nor too gently to better protect your gums. The Gum Protection feature alerts you when you've been brushing too hard. Replace the Oral-B iO toothbrush head every 3 months for best results.    Oral-B's BEST CLEAN with REVOLUTIONARY iO TECHNOLOGY for a professional cleaning feeling every day