This gives a bit of a lift to the air going over the screen. it is effective. I had it fit to my Sprint GT, but I know it fits Triumph Sprint St fro on. Probably others but I don't know.
It cost me US$130 so this is a good buy for someone.
I drilled and extra pair of holes, and cracked one bit, repaired it with professional acrylic glue and is good - but there.