This did NOT work for us at all. We have been treating our hair for months and finally got this. It did not detect any lice. I used it for hours on my hair and my daughters hair, too. Our heads were still itching. The next day we used LiceFree spray and loads of tiny lice and nymphs came out. I was shocked to see so many. The comb was functioning correctly, just not detecting any of these tiny lice.