This book reading light provides 3 color temperatures x 3 brightness settings(Low, Medium, High ). You can adjust 9 different kinds of brightness levels dimmable by one button which is on the reading light. The 1600K saves you from blue light especially when reading in bed at night; the 4200K can easily create a relaxing ambiance for your leisure reading; the 6000K will aid your focus at work or studying. Rechargable, comes with a USB cable, design with clip, can firm it on your pad, book, or desk, very convenient to use, especial when you have a trip.