Features: ANTIMICROBIAL PRODUCT PROTECTION Cleaner skin begins with a cleaner brushTM... Skin cells and moisture remaining on the brush heads between uses can create conditions for bacteria to grow. SONICLEAR brush heads are treated during the manufacturing process with proprietary LIFE antimicrobial product protection ~ a soniclear exclusive ~ to guard against stain and odor causing bacteria. The antimicrobial protection in soniclear combines silver-based technology registered with the US Environmental Protection Agency and patent-pending natural plant extracts technology. Together these technologies guard against stain and odor causing bacteria on the brush heads of your soniclear. Safe, effective and long lasting, the antimicrobial protection will not wash out or wear off for the normal life of the brush heads so the brushes stay cleaner, fresher for longer!