The Penny & Giles Joystick II has a USB connector and will work on both Mac and Windows computers that have a USB port. It also comes with a USB-PS/2 adapter so it will work with a computer that has a PS/2 port. The Roller II has 3 buttons that work as follows: the left (yellow) and right (blue) keys operate as left and right mouse keys. The center (green) key is used to select the left drag function. Three switch jacks allow external switches to be connected and parallel the function of the mouse switches.