The Bescor 5V USB to 8V Power Converter for DC Coupler/Dummy Batteries features a USB Type-A connector that plugs into any 5 VDC USB port and provides 8 VDC power output via a 2.1mm coaxial connector. The cable is power-regulated and the output voltage is well suited for powering cameras that use a 7.4 VDC battery. The coaxial/barrel power connector allows you to connect an optional DC coupler/dummy battery to the cable to provide power to your DSLR or mirrorless camera.