Oral-B's improved Precision Clean toothbrush heads are developed with CleanMaximiser technology which causes the bristles to change color from green to yellow when it's time to replace the brush head for optimal brush head performance and the best possible cleaning The unique bristles brush away plaque for a superior tooth-by-tooth cleaning compared to a regular, manual toothbrush. Fits all Oral-B handles, except Pulsonic and iO. • The unique bristles brush away plaque for a superior tooth-by-tooth cleaning compared to a regular manual toothbrush • Removes up to 100% more plaque for healthier gums compared to a regular manual toothbrush • With CleanMaximiser technology that makes the bristles change color from green to yellow when it's time to replace the brush head • Replace every 3rd month for best cleaning • Fits all Oral-B handles, except Pulsonic and iO