Ultra-short throw, or UST, is an important feature when you have a small space that doesn't allow for a projector to be five to six feet back from the screen. UST projectors will enable you to place the projector less than two feet from your wall or screen, in some cases as close as just a few inches. It is also ideal for situations where people or objects may pass in front of the projector, where they would typically obstruct the light.