Screen Innovations says that its Black Diamond ambient light rejection screen technology is what makes this screen unique. Utilizing one motor, four custom helixes and a spool of slender aircraft cable, Black Diamond Motorized lowers a thin wing containing the rolled Black Diamond screen downward from a recessed ceiling-mounted cassette. The cable-hung wing then stops, and from it, a small tube quickly emerges and lowers itself down to an adjustable, pre-determined image height, leaving only the image space in sight. Because Black Diamond screens do not require masking or any black drop material whatsoever, there is no visible material above, below, or on either side of the screen surface, allowing the images projected on Black Diamond Motorized to appear as though they are suspended in air.
Here are all the specs: http://www.screeninnovations.com