With the exception of Shrek, I believe all of the 3D at Universal now use Wavelength multiplex visualization. where there is an offset of color from one side, which the glasses then correct. The advantage of this over polarized is the image is brighter, there is less crosstalk and the 3D is sharper. The downside the glasses are more expensive (and not disposable) and the projection is more expensive. Very few theaters have it, but its marketed under Dolby 3D (which is actually advertised in Star Tours at Disney). The easiest way to tell is polarized glasses appear grey, where as Dolby 3D appear slighty different colors.