Optoma EH320USTI Ultra Short Throw Interactive ProjectorOptoma's 1080p ultra short throw interactive projector, the EH320USTi, is perfect for businesses, schools and colleges. It is bright (4,000 Lumens) and uses TouchBeam finger touch interactive technology, enabling several people to work simultaneously on the screen without using a pen. The throw ratio of 0. 25: 1 means that it can project a 100" image from just 55cm away. SPECIFICATIONS Brightness: 4,000 Lumens Contrast: 20,000: 1 (full on off)