Medical Isolation Transformer

How safe your device would be if it were to purely run on the beast surge of Direct Current of electricity? Would you derive maximum utility from an Electrical appliance if it had to rely on the non-sustained charge of a couple of batteries?
Miracle’s Medical Isolation Transformers have the ability to do what is precisely required by them – lower the voltage exactly to a value that is required by the appliance and keep them running right and safe