1. Food grade PP material brush head, safe and harmless. DuPont bristles, soft and flexible. 2. Sonic vibration technology, 4000 times/min vibration frequency. 3. Powered by 1 x AAA battery (not included), and it can work for about 60 days. 4. Size: 19*1.6*1.6mm 5. Net weight: 20g
