Key features:

• It gives a next-level clean with 40,000 micro-brushes per minute gives you over a month's worth of manual brush strokes in less than two minutes. 
• It has a powerful sonic movement that whips up toothpaste into microbubbles, driving them deep between teeth and along the gum line for gentle, effective cleaning.
• Encourage a brushing habit - comes with a 2 minutes smart timer, it automatically shuts off when two minutes are up. Remind you to change the brushing area by intelligently pausing every 30 seconds. Plus, the brush heads remind you to replace in time through blue indicator bristles.
• 5 intensity settings just for you that allows you to customize your brushing experience with a choice with 5 modes. Choose white when you want to eliminate stubborn plaques and stains while pressing the massage button to take care of your gum with inverted frequency.
• IPX7 WATER RESISTANT features high water resistance, it can be totally rinsed in water without any damage. 
• The ADA is the professional association of dentists dedicated to serving both the public and the profession of dentistry. 
• The reason why 507 brush can get this approval is that the association finds it is safe and has shown efficiency in removing plague and preventing gingivitis.