[Innovative 4D Keystone Correction & Zoom Function] Our HD projector is the first projector with 50 ° 4D (vertical & horizontal) keystone correction function to ensure the projected image is always a standard rectangle. It’s very convenient to adjust the screen by using the remote control, especially for the projector suspended from ceiling. Reducing projection size by using the X/Y Zoom function, while others can only do that by changing the projection distance.