USB rechargeable long-lasting : clip on the book reading light built-in 500mAh battery, only need to charge up to 1.5H to use 10-80H. USB socket can be plugged into the laptop, mobile power and car charger on direct charging, the indicator light shows red when charging, the indicator light shows blue when the electricity is full. Adjustability and Portability : The head of the reading Light can be rotated 90 left and right and adjusted 45 down, and the clip can be expanded up to 120 to illuminate exactly where you need to light. USB rechargeable Book Light weighs 40 grams and is small in size, so you can take the Book Clip Light with you wherever you go. Eye protection Timing function : The reading lamp of the book light is soft and non-blinding, anti-dazzling, CRI95 Ra. It will be more friendly to the eyes of people who need lighting for a long time in the dark. Timing function just long press the brightness button for 3s, the light will flash twice to indicate the timing of 30 minutes.