If you are referring to the one that is on this picture on this page it's a memphis shades gaintley with a laminar lip on it for 49mm. They also make them for 39mm
What kind of fairing is that? Is your front end 39mm? I have Arlen Ness but it vibrates a little. I like the look of HD fairing, especially the clear light cover. Its hard to find mounting hardware for 49mm.