Superior Industrial Materials. Product Description Description: Easily add up to 4 devices with the Sabrent USB 2.0 Hub. Particularly great for recent notebooks that provide a limited number of USB ports. Achieve full 480 Mbps on each port, or daisy-chain multiple hubs to a maximum of 127 devices. Fully backwards compatible with the USB 1.1 products. Please Note: For a stable connection, the devices connected to the 4 Port Hub must not exceed a combined current of 5 volts 500mAh. External hard-drives should be connected to an external power source. This 4 Port hub will not charge your devices, it will only sync them. Compatible With Most Operating Systems - Windows 2000/XP/Vista/7/8/8.1/10. - Mac OS 9.1 & Higher. - Linux 2.4 or Above.