4 Options:

1) Red Light – Promotes hair growth

2) Blue Light – Reduces oil production

3) Vibration – Increases blood flow to scalp

4) Electrical Muscle Stimulation (EMS) - low-frequency muscle stimulation technology that unblocks clogged pores, enhances hair nutrient absorption, and strengthens hair roots. By sending small electrical currents into the scalp, EMS can help to improve blood flow, reduce inflammation, and increase the delivery of nutrients to the hair follicles.

FYI -- Device manufacturer encourages to try on face/body and not just the hair.