I finally got tired of having my eyes watering from wind blowing into the bottom of my Scorpion EXO 700.
I had tried the Scorpion chin curtain. It helped a little, but I still got wind blowing in.
I saw one of the Quiet Riders in a catalog and ordered one from my local shop when I stopped in the other day. Man, what a difference! It make a nice seal around my neck and keeps all wind out of the helmet. I am sure it will also keep out dust and floating "stuff" in the air. I had thought it would be difficult to get the strap done up with it installed. That turned out to be a non-issue.
Here is a link to what I am talking about. Linky
If you have similar issues, I would recommend this inexpensive fix.