1.Wide Compatibility Compatible with all Water Pik Sonic Fusion and Sonic Fusion Professional Flossing Toothbrush models whose model number begins with SF-01,SF-02, SF-03, SF-04. Check your model number on the bottom of your toothbrush base before purchasing. 2.High-Quality & Cost-Effective - Many years of experience in toothbrush head production and using bristles the same as the Name brand ones, ensure that you can save money without compromising quality. By choosing these 6 pack toothbrush heads, you can maintain exceptional oral hygiene without breaking the bank 3.Always Know when to replace - The blue bristles will fade in color over time, alerting you when it's time to replace the brush head, ensuring you get an effective clean. 4.Gentle Bristles & Effective Clean - Made of US Dupont round-end bristles, world-famous for their top-quality and trustworthy performance. These flossing brush heads can fit naturally to the shape of your teeth and gum, easily remove stubborn plaque, avoid damaging sensitive gums and bring comfortable deeper cleaning.