I asked Dr John Harris this question over the weekend when I saw him at World Vitiligo Day. He said that the two companies he typically recommended - Daavlin and National Biological - recently merged. You might look for those brands. He said that the large - 7 foot tall units he recommends cost $5000 to $6000 and are not usually covered by insurance but they work great and are much easier to use regularly since you don’t have to go into the office. Hope this helps!