?Wide Compatibility?: Compatible with Fairywill DrDent Compatible with Initio IT959electric toothbrush FW-507/FW-508/551/2011/917/959/D1/D3/D7/D8. Compatible with atmoko model HP126AB/hp126a. For more brands and models, please consult seller before order. ?Easy to Install?: Contra-rotate to take out old head and clockwise rotation for refilling new one, easy replacement. ?Teeth Protection?: 95%-98% top of bristle rounded before packaging. Just considering protecting your teeth when brushing in high vibration. The teeth enamel would get worn if bristle was not rounded. ?"w" Shape Bristle?: Shape of bristle is designed in "W" shape thus the head can fit to your teeth well. A great shape for efficiently brush and removing more plaque and stains. ?Sanitary Packed?: Each replacement head equipped with dust cover then sealed into plastic bag and together packed in paper box. Three layers of protection avoid dust pollution during packing and transportation. Also, dust cover is perfect for travel, keeping your head free from germs & stains.