The Brio XClean replacement brush heads are one of the largest brush heads available for a sonic toothbrush! The larger size and crisscross pattern of the bristles cleans multiple teeth at one time and leaves your mouth and gums with a deep clean! All Brio brush heads are designed to fit with any Brio toothbrush. Brush heads should be replaced every 3 months or sooner depending on wear. If you are wearing them out much sooner than that, you are probably brushing too hard, so take it easy. Keep the heads in their hygienic resealable package until they are ready for use.