These parts were casted under pressure in a translucent material. The benefit to these new parts is they help diffuse and disperse the light better compared to the original clear parts that allowed you to see right through. No diffusion is needed on these new parts, simply install and you are good to go. See photos as they do a better job showing the differences. These parts were casted in a translucent white, however color can be added during the casting process to make them red, blue, or whatever color you want.