Radicals are atoms with a missing electron. Since most chemical reactions use pairs of electrons. Free radicals are atoms, typically oxygen, that have this missing electron. They are super reactive and will steal an electron from the first atom or molecule they can. That atom/molecule then goes and repeats the process, creating a chain of radicals that can mess up your tissues. Typically our body uses anti-oxidants to halt radical chains, but it is very intense and can only be done so much. That ozone machine has no benefits and loads of potential drawbacks.