The multi-monitor display extension app, spacedesk lets you use other devices and computers on your LAN (Local Area Network) as monitors for your Windows desktop. At least 2 machines are needed to operate spacedesk. These machines are connected via a network and running two different software programs: 1. The Primary Machine is a Windows PC, laptop or Surface Pro tablet. It runs the spacedesk DRIVER software. It includes network display server software and display device drivers.