I wanted to weigh in here as well. I have used these for a long time and they do work but require a little adjustment when you're flying with them. You have to careful to point the controller in the"general" direction of the drone. The beam spread is pretty wide (about 120 degree from what I've tested) but if you turn away from the drone, they are pretty unforgiving. In addition to the parabolic advantages, which are used in everything from Dish TV setups to the sky beacons that are used for large parties, you also improve your antenna alignment. Using a set of these force your antenna into an exact parallel relationship, which is optimal for signal strength especially at long distances. My experience in a wide variety of locations is that these can add 50% or more distance to your flight. The alternative is to use an upgrade kit like the ARGtek to increase it even further. I did a test with an EMF meter a while back that you can watch below to show you the signal improvement.