Amazing. I was recommended these lights by a friend who is a chiropractor and also a user of the original Platinum LED line. I purchased the BioMax 450 and 900, and cannot say enough wonderful things about not only the quality of the product, but also the quality of the experience. I use these lights regularly, for several hours a day, and have noticed a significant improvement in the quality of my sleep, digestion, mood, energy, and overall quality of life. Having two units allows me to target front and back, L&R sides simultaneously; and having the smaller 450 unit allows me the portability to bring it into various rooms in the house for use while doing various activities like working at my computer, hosting zoom meetings (camera off, of course!), and watching television. I cannot say enough positive things about them! Thank you PlatinumLED for making such a high quality product!