What do you know about micro current therapy? Good/bad?

The one I’m looking to use is- 

I asked about EMF. Here’s what the company said about EMF exposure-

EMF exposure is extremely minimal. The units are operated by 2xAA batteries so they don't need a lot of power to run and are not plugged into the walls at all. The devices output a mild PEMF field at what is considered "earth level frequencies" - close to 300 milligauss.