16,000 gentle sonic brush strokes per minute Unique high-low pattern of soft, end-rounded bristles effectively cleans plaque from hard-to-reach areas Includes replaceable AAA battery Waterpik Nano Sonic toothbrush is 16,000 strokes per minute and a frequency of 133hz which falls in the definition of a sonic toothbrush.Sonic waves are not part of the product claim Any warranty will be voided through the sale and use of the product outside North America. Shipment outside of North America is prohibited by Waterpik