Terabyte 4 Port switch allows Four CPU or devices to share a single display device device like monitor or projector with just press of a button - switching the button to select a different display at a time, but cannot be displayed simultaneously. It does not use any external power. ? With it's compact size and light weight, it is portable and easy to carry while travelling. ? It is a perfect device for Connecting a projector and monitor and if you have single monitor between 4 pcs and want to operate them one by one This is a compact and convenient VGA bi-directional manual switch. ? It allows 4 PCs to share a VGA display, or switching 1 PC between Four displays. ? Designed for securities market, education, public system, video broadcast system and other environments. ? Plug and play, no power supply needed. ? 5 standard 15 pin VGA connectors: 1 in 4 out ? Easy to install, no additional software and power supply needed ? 4 PC to 1 monitor, 4 monitor to 1 PC, 4 DVDs with VGA to 1 ? Manual button control to switch ? monitor, LCD, Plasma TV set ? Fully shielded metal case, anti-slid feet