This mini USB hub has four USB 2.0 ports each with a max total transmission speed up to 480 MBps. All four ports are powered thru the USB micro-B cable. There's also a single on-off switch that controls the four USB ports. There is a 1.7mm port for an external power supply but its connected directly to the 5V line so if you need to externally power, we recommend prying open the case and cutting the red 5V line from the USB connection.