This USB to 3/4pin cable is 5V USB to 3pin/4pin fan cable, it allows you to power most case fans by using a USB connection
Cable connector: 1x USB port, 1x 3 pin/4 pin case fan power adapter cable port(compatible with 3 pin / 4 pin PC fan)
USB to 3/4pin PWM PC fan compatible with desktop computer, notebook computer, USB adapter
The voltage of cable only supports 5V, which is only suitable for PC fans working at 5V. PC fan with 12V is not applicable.
5V USB port to a small 3-pin/4-pin fan cable allows to use USB connection to power most chassis fans, either 3pin or 4pin chassis fan power adapter cables.