The Mi Electric Toothbrush T100 Brush Head is a replacement head set featuring ultra-soft bristles designed specifically for the Mi T100 electric toothbrush model. Each package contains 3 replacement brush heads to ensure continued optimal cleaning performance. As this is a personal hygiene product, it's recommended to replace your toothbrush head every 3-4 months or sooner if the bristles become frayed. These brush heads are compatible only with the Mi Electric Toothbrush T100 model.