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