Not Authentic
I already own this product that I purchased from a dentist 7 years ago... it still works great.  I purchased this one to use while traveling and it sounds like a lawn mower compared to my other unit.  It's very loud with a strong vibration.  It works - but isn't as smooth as the original.  The original Sonicare I purchased for over $100 and this one cost $20... so I guess you get what you pay for!?!?
Rating: 2 stars