*ORAL B IO CLEAN & GUM PROTECT SENSITIVE BLACK REFILL BRUSH HEADS 4 PACK[GENUINE] The Oral B iO series Clean & Gum Protect Replacement Brush Heads combine powerful but gentle micro vibrations with our unique, dentist inspired round brush head design for Healthier Gums in 1 week*. Designed exclusively for Oral B iO electric toothbrush handles, Oral B iO Clean & Gum Protect brush head is specially designed for gentle and effective cleaning on sensitive areas and gums. It has up to 4000 densely arranged bristles to clean