Frisby Self Powered 4-port USB 2.0 HUB for Computer Notebook PC Mac 4 PORT,USB 2.0, WORLDS SMALLEST USB HUB 1.1 compliant and USB-IF certified With internal voltage regulator, Frisby SXH020 provides +5Volt operating voltage to conserve power Does not require electrical adapter, it is self powered Supports both low ( 1.5 Mbps ) or high ( 480 Mbps ) transfer speed