[Update] This reading lamp provides three color temperatures. Custom setting of 3000K (warm yellow), 5500K (white) or 4500K (warm white), brightness adjustable from 15%~100%, maximum brightness: 50 lumens. Variable intensity and eye protection. Built-in 250 Mah rechargeable lithium battery. Book light with clip: a plastic clip, commonly used in e-readers, books, etc., which can be used as a bookmark on the back of the bed. There is a magnet at the bottom of the clamp which allows you to easily fix the reading light at any position with the magnet. [USB Recharge] 250Mah rechargeable lithium battery connected to a laptop, a mobile phone adapter and even a portable charger. Full charge only lasts 40 minutes and allows uninterrupted use for more than 4 hours. The red LED lights up when charged and automatically turns off when fully charged. [Small and Flexible] Very small and light, easy to carry. The rubber material makes it flexible and can be bent 360 degrees for maximum light exposure. Mini - sizes can be placed in travel bags, laptops, computers, night reading, music racks, etc. [size] 20.5 * 4 * 0.9 cm