The "3D ready" designation for a projector means that the device has the technical capability to process and display a three-dimensional image. To be able to do this, the projector must support a high refresh rate, typically 120 Hz. This allows it to project 120 frames per second, with rapidly alternating images designed for the left and right eye. This rapid alternation creates the illusion of spatial depth for the viewer. However, the "3D ready" label alone does not guarantee a complete 3D experience out of the box. In addition to the projector, a 3D signal source, such as a 3D Blu-ray player or a computer with a matching graphics card, and of course a 3D movie or game are required to fully view 3D content. The most important part is the special active 3D glasses that synchronise with the projector and filter the image so that each eye sees only the images intended for it. Without these accessories, the 3D effect cannot be achieved. This parameter therefore informs about the projector's readiness for 3D technology, not about the complete solution.