1.USB to PS2 Adapter 2.Windows 98 , SE / ME / 2000 / XP / Vista Supported 3.Two PS/2 Keyboard or Mouse Suppoted. usb adapterUSB A male to PS2 Female Adaptor;Fully Compliant with PS/2 Keyboard & Mouse Driver Free Designated , Just Plug & Play and Hot Swappable Allowed Windows 98 , SE / ME / 2000 / XP / Vista SupportedMac OS Supported