Full Compatibility- brush heads are specially designed and perfectly compatible with fairywill electric toothbrush replacement head handles ( FW-D1/FW-D3/FW-D7/FW-D8/FW-507/508/551/FW908/FW910/917/949/958/959/FW610/FW659/FW719So Comfortable and Durable- Feel the difference of US genuine Soft DuPont bristles ( the same as name brand 100%). Our brush heads have the Higher Ratio End-Rounded bristles,which care for teeth and gums, making you feel more comfortable brushing experience like never before.Effective Cleaning - Smile with Confidence US genuine Dupont bristles with power vibration easily removes more plaque, Curved shape design achieves a thorough cleaning at hard-to-reach areas, making your teeth much whiterPerfect Stable Operation- Superb PP material ensures that the brush head Never break and the bristles Never fall off No matter how long you use the replacement toothbrush heads, there is no any troubles here, Enjoy every pleasant brushing time.100% Money Back Guarantee- We truly want you to be happy with your new replacement heads and our professional customer service will do whatever it takes to ensure your satisfaction we are offering a 6-month guarantee, no questions asked.