I saw this in action the other day. We went to see Gov't Mule with Jackie Greene opening. The venue (Bank of America Pavilion) is a big tent open on the sides. It's generally not windy, but it was that day. I left my "big ass shure" windscreens in the car and only had the light duty wind screens. For Jackie I was going to run 480's with CK61 card caps, but I could see the wind peaking the meters when we set up. I switched to omni caps and had no problems. I changed over for Mule... I was going to run the JZ BT201 cards, but the wind was still a problem. I switched to the "Open Card" caps (which I interpret as kind of a sub-card cap) and wind was not a problem.