3 levels of brightness, On and Off, are available by touching the sensor area around the base ring of the clamp after turning on the master On/Off switch. Choose between low, medium, or high brightness levels to match your needs. Great reading light for bed,desk,headboard. 50000 hours long lifespan saves you from years of maintenance and replacement. The width of the strong clip is 7.2cm. Clip on desk, bed or headboard or where ever you need. Clamp light Brings you convenient life! This clip on reading light uses high-quality 4W LEDs which saves up to 80% of energy used by traditional lamps, yet still provides you the same brightness. No flicker, No dark areas, No ghosting and low HEV help eliminate the visual fatigue caused by the stroboscopic effect of traditional light sources. Protect your eyes when you are reading, drawing, working, studying The modern and flexible gooseneck can be adjusted 360 degrees, you can adjust the lamp freely for the best viewing angle. The super long cord enables the reading light to be conveniently placed anywhere, no worry about the distance between the desk lamp and socket