This 3-watt clip-on LED desk lamp is a perfect lamp for the office， dorm room， bedroom， or any place where you need an adjustable brightness light. It uses 16 individual 4000 K neutral white LEDs， rated for 20，000 hours of use and arranged in a 4.3-inch ring， with frosted plastic to diffuse the light. This flicker-free clip-on LED desk lamp can be attached to surfaces up to 1 inch thick or you can simply place the stable 4.7 x 2.6-inch clip-on base on any flat surface. Turning the desk lamp LED on or off and switching between the 3 brightness levels， with up to 240 lumens of brightness， is as simple as touching the button on the base. The 19.3-inch flexible silicone neck allows you to position the light angle for the desired level and focus of illumination. The light is powered using a USB power source (not included) and features a 500mAh rechargeable battery， which can provide up to 3 hours of operation on a 2-3 hour charge. A 59-inch USB Type-A to Micro Type-B cable is included.