When I purchased this I thought that is very low price for an ozone generator with that high an output. When I turned it on, I realized they were giving very misleading ratings, as the output wasn't any where near 600 Mg per hour. It is a trick some Chinese manufactures use to sell their product. They advertise the output based on supplying it pure oxygen and hope you won't realize it is much lower when used in normal air. Sure enough, if you look on the back of the machine, the label says ozone output 600 mg/h 02 In. O2 is pure oxygen, however the air we breath is only about 20 % oxygen, so the actual output is only about about 120 mg per hour. Since the label says the rating is based on O2, it is technically accurate, but you don't see the label until after you purchase the machine. Plus there is no oxygen connection that would even allow you to hook up an oxygen tank to the generator, so there is now way to get the output they advertise.