This portable reading light is an excellent product. It is low-priced, high quality and high performance. The light can be set at two brightness levels (one or two individual LED's on), and even the lower level is usually bright enough to read comfortably. I carry this in my attache for reading my textbooks in Starbucks and libraries, where overhead lighting can be dim or inconsistent. If the ambient light changes because of sunlight, it is easy to switch the light off, the on/off button is super easy to operate. The clamp is very strong but is shaped in a way that protects the book and pages, it doesn't leave any marks or indents on the book or paper. And the adjustable neck is very high quality, it adjusts to infinite positions and stays right where you bend it.