There are 2 types of Alpha-Stim devices: CES and MET devices.   The CES, or "Cranial Electrotherapy Stimulation" unit uses ear lobe clips. It treats anxiety, depression and insomnia. As a result, this unit is also often referred to as the AID unit "Anxiety, Insomnia, Depression".   The MET, or "Microcurrent Electrical Therapy" unit uses electrode probes or patches to treat pain. This treatment is then finished with cranial electrotherapy stimulation via ear clips, which are included in the MET kit as well. Therefore, with a MET unit, you can treat pain, and have the added benefit of improved mood, relaxation and sleep even if you do not suffer from problems in these areas!