Is there a difference between the escort 8500x50 gray vs black?

I went to order an escort passport 8500x50 on amazon and there are gray ones as well as black ones. The gray ones are cheaper and when I clicked it it gave me an option of selecting the upgraded version which was the black one. Is there a difference between these two or is just the color? Thanks

The new 8500/X50 Black has a corrective lens (plano convex) which gives it better detection range than the older model. Some have also indicated the audio alert ramp up seems more accurate and in-line with received signal strength.