Aten Auto Peripheral Switch 4x1 USB 2.0, 4x PC, 1x USB 2.0 Ports, Auto Port Selector, Confirgurable Via Software, Hot PluggableThe US421A is a 4 port USB 2. 0 Peripheral Switch that allows up to 4 computers to share the use of a single USB peripheral device (such as a printer, scanner, mass storage drive, etc.) on a one at a time basis. The peripheral focus can be given to a computer manually by using pushbuttons on the switch, using the software based configuration utility, or by the Auto Switch function. Compatible with both Windows and Mac, and with multifunction printer