These brush heads are meant to be used with Oral-B iO electric toothbrush handlesThe design of these replacement brush heads helps you brush hard-to-reach spots, for a clean that you'll truly feelWhen used with Oral-B's iO electric toothbrush handles, these replacement heads employ gentle micro-vibrations that help to clean your teeth and gums betterDual-length bristles surround your teeth and reach deep withinIt is recommended that you change your toothbrush head every three months to ensure that you achieve the best cleaning resultsThis set includes two Oral-B iO ultimate clean replacement brush heads