Extramon lets you use a second computer as a second monitor, giving you a dual-monitor computer. You can operate them both from a single keyboard and mouse. Extramon sends video across the network and displays it on the other computer's monitor. Extramon has an on-screen switch that allows you to choose which computer you're looking at. You can place your laptop computer beside your desktop's monitor or use you can use the software on two desktop computers if they're both on your desk.