Clarisonic Brush Heads oscillate back and forth at over 300 movements per second, gently flexing the skin. This motion releases dirt and oil within the pores and sweeps away dead skin cells, impurities, and environmental pollutants. Clarisonic brush head bristles are cut to varied lengths on each type of brush head, with the longest length providing the most plush feel. This offers different levels of gentleness, while each is equally effective. Compatible with every model, our soft-bristle facial brush heads vary to accommodate a range of skin types and should be replaced every 3 months.