Thought there was another thread on this but I couldn't find it, so here's my opinion. I bought the Klockwerks sheild for my FLHT. Tried it once and wasn't crazy about it and took it off. Yesterday, I thought I'd try it again. In the morning with fairly calm winds it was fine. In the afternoon, the winds picked up to about 15-20 mph and it was pretty much useless. I checked the Klockwerks site and they're now offering a 10.5" shield that I think would be better. But I'm thinking I might try one from Cee Baileys
ceebaileys.com
On mine they offer sizes from 9" to 15" and they're a lot cheaper.