Philips Sonicare HX9042 Diamond Clean Smart Brush Heads adapts to the contours of your teeth and gums thanks to soft, flexing sides that give you 4x more surface contact than a regular brush head for a comfortable, deep clean. The Smart Brush Head syncs with your BrushSync™ enabled Philips Sonicare toothbrush handle, selecting the optimal brushing mode and intensity level for exceptional cleaning. All you need to do is start brushing. Soft rubber sides flex to let C3 Premium Plaque Defense adapt to the shape of your teeth and gums, absorbing any excess brushing pressure and enhancing our sonic cleaning power. Bristles can then adjust to the shape of your teeth and gums so you get up to 4x more surface contact than a regular brush head for deeper cleaning in hard-to-reach areas.