The lamb doesn抰 need power supply, instead, it only need to be connected to the telephone line. That is, you don抰 have to pay for the light! Beautiful shape and fashion design; free light from telephone line and no worry about power cut. The bulb is made with durable led lamp, the use life is longer than 100,000 hours. With clamp holder, the lamp can be put on the desk and also fixed on the edge of the desk to save the space and strengthened the light to protect you eyes!