This replacement head for the FOREO ISSA toothbrush features a hybrid design, combining soft, medical-grade silicone outer bristles with durable PBT polymer inner bristles. This construction offers a comprehensive approach to oral hygiene, ensuring effective plaque removal while remaining gentle on the gums. Ideal for maintaining the optimal performance of your ISSA toothbrush, the hybrid design balances durability and thorough cleaning action. It is designed for daily use to support superior brushing results.