I spent hours comparing different red light devices and ultimately purchased the AllevaRed Pro Light Therapy Belt for myself (along with the compatible Powerbank). So far I am very happy with it. Instructions are easy to understand so I wasn't nervous to use it. So far I have found relief for my left knee which has been problematic for weeks and also my lower back - have not noticed nearly as much pain or flare up since incorporating this device in my routine.
I love this belt so much, I got it to help my stomach recover after having my baby, I bought it 3 months ago and didn't unbox it until a month in a half ago after I gave birth and when I went to put it on today none of the lights worked. I bought the battery pack and everything, I'm super bummed it's not working as I have not really used it but maybe 15 times.