ACRYLITE® LED coloring changing back lit has a new formulation that provides improved results when backlit with LEDS. Superior diffusion effectively hides LED hot spots when backlit, eliminating the need for the diffuser films required by the older cast formulation with LED lights in standard channel letter designs. It’s manufactured from a special pigment formulation that yields 25 percent light transmittance when backlit, but appears dark and opaque without backlighting.