Mounted in front of the projector lens, this filter is synchronised to the projected images, giving each frame a polarisation perpendicular to the previous one, which can be viewed with polarized 3D glasses. In earlier, the filter wheel can be lowered out of the lens’ path for non-3D material. It has been noted that an earlier version of the spinning polarized filter malfunctioned, but the problem has been addressed with an updated replacement filter which was supplied to all theatres using the electronic shutter method system.