Hi all roadster. Did a search in the forum but I can't find any info about this. Lately, I saw alot of cars being new or old and I saw their headlight got some kind of coating which a transparent headlight will have a coating like it's in blueish and some are in cromax color. I see that it's nice. Besides being nice, I'm sure it will protect the headlight as well.

Any idea what treatment it is and where it's being done? 
Thank you.