Note: Please confirm the size and specifications of the DC connector before purchasing to avoid being unusable after purchase.(Reference 3.5mm is the size of the headphone cable plug, 5.5mm will be slightly larger than it). Function: Boost power supply for router,radiator,usb hub,usb lamp,usb fan,usb speaker etc. Length: 1 meter Package include:1pc USB DC 5V to 12V Boost Cable