Perfect Compatibility: Bullnas replacement brush heads are fully compatible with Philips Sonicare 4100 5100 5300 6100 handles, for ProtectiveClean, DiamondClean, EasyClean, FlexCare, FlexCare+, FlexCare Platinum. HealthyWhite and HydroClean Brush Handles, providing exceptional cleaning performance, so you can enjoy professional-grade oral care. Efficient Cleaning: Up to 7x more plaque removal versus a manual toothbrush. Their W design surfaces ensures a tight fit along the surface of your teeth and reaches deep into hard-to-clean areas between your teeth for a complete, refreshing clean. Gentle Care: Bullnas replacement brush heads are made with dense, flexible bristles that are gentle yet effective. They easily remove stains and plaque while gently caring for your gums, providing you with a comfortable and thorough brushing experience. Visual Bristles: Each Bullnas toothbrush replacement heads features color-changing bristles that gradually shift from blue to white as you use it, clearly indicating when it’s time to replace the brush head. Dentists recommend replacing your brush head every 3 months to maintain optimal cleaning performance. Included Dust Cap: Each replacement head comes with a dust travel case that helps protect against dust and debris, ensuring a clean and fresh brush head every time you use it. Enjoy a hygienic and worry-free brushing experience. Bullnas Replacement Brush Heads compatible with Philips Sonicare, Toothbrush Heads for Sonicare ProtectiveClean 4100 5100 5300 6100 Electric Toothbrush, 12 Count Ultimate Care Toothbrush Heads, Black