The NEC NP-PA550W Professional Installation Projector with NP13ZL Lens is one of NEC's stackable projectors. No, you don't stack them on top of each other. You can place up to four of them side by side in a row to project one luminously bright and perfectly aligned image. With four NP-PA550Ws that's an image. That's an incredible 22,000 lumens bright. It's ideal for larger sized screens. The NP-PA550W can project a 500" (12,700mm) image or where there is a great deal of ambient light. This feature also prevents the complete loss of an image, which can happen when using only one projector.
This product comes with a 1 year warranty