Maintaining good oral health is easy with the Philips Sonicare e-Series Standard toothbrush heads. These screw-on replacement brush heads remove up to 2x more plaque vs. a manual toothbrush. e-Series also features an angled neck and contoured bristles to help you easily maneuver the brush and focus on hard-to-reach areas where plaque can hide. The blue reminder bristles fade to let you know when its time for replacement. Replace your brush head every 3 months as recommended by the American Dental Association. A fresh brush head every 3 months maximizes the effectiveness of Philips unique Sonicare technology.