The interdental tips of the brush with soft sensitive fibers made from special Convex Nylon penetrate even the most difficult-to-reach areas of the teeth. - Ultra soft brushes - Waterproof IPX6 - Effective convex shape with soft bristles - Toothbrush head replacement Cleaning and care: Do not use bleach, do not sterilize with microwaves or steam sterilizers. Material: ABS, PP, rubber, nylon. Dentists recommend replacing the brush every 3 months or sooner if wear is observed.