Physics of Dirty Electricity?
The language used by the sellers of this device is not particularly scientific. It appears likely to be a placebo device marketed to (self-described) sufferers of "electrosensitivity". There is no scientific basis for these claims, and this device is unlikely to have any real function. The advertisement and sale of such devices has been prosecuted in some countries under false advertising laws.

There is some limited truth to the concept of "dirty electricity" in relation to electrical devices, but it bears little relation to what appears in the marketing information for this device. Most notably, it does not have effects on human health, and cannot be effectively filtered by a plug-in device of this nature.