Worked exactly as intended and killer lice after one treatment. I had been fighting a small outbreak of lice from September to October 2018. Once we got this, it was one and done. I bought extra heads from the manufacturer directly to have on hand for a future problem. Excellent product that Inhighly recommenced. It is not cheap, but one treatment at the salon would cost the same. So, since I have two girls that may get lice again, this was an excellent investment.