Posted by a reviewer on Amazon

I think some water got in and it was having a bit of issues turning on and off but after letting it dry for a day it worked fine again

Posted by a reviewer on Amazon

See original post below after this update

Posted by a reviewer on Amazon

So here is why it deserves a 5 star rating

Posted by a reviewer on Amazon

Definitely improves whitening we monitored and the results were very noticeable

Posted by a reviewer on Amazon

Unfortunately hers lasted less then two weeks and the light no longer comes on

Posted by a reviewer on Amazon

Great mouth piece fits well just very disappointing that the unit is out of warranty and cannot be exchanged for a functioning unit

Posted by a reviewer on Amazon

So here is the bottom line i would give it 5 stars for the first unit still working and 2 stars for the second unit with good mouth piece but light went out in less then 2 weeks

Posted by a reviewer on Amazon

The size of the device should fit both male and female and maybe even youth mouth sizes because its a little short and doesnt cover that final set of molars in my somewhat small mouth