E3L Lighting Ever Flexible USB Rechargeable, 3 Mode Touch Modern LED Desk Lamp, Reading Lamp, Book Light, Task Light,black Touch sensor switch-single touch give lowest brightness, double touches medium and three touches the strongest 3-level adjustable brightness Free twist tube-Multiple adjustable positions for best comfort, can use in office, bedroom, school, and reading; Easy folding Cycle charge led light-the lamp will last 12 hours consecutively in the dimmest light; 10 hours in medium light ad 8 hours in brightest USB-can be plugged into your computer's USB port. No batteries needed