I bought a Canon 600 ex rt ll flash that I use a Better Beamer on. There is a little bit of play in the head when positioned to shoot straight ahead and it drops down slightly. The result is only the lower half of the image is flashed. My solution for now is a shim to hold the head in position. I wish the head would lock more solidly in position. I also don't find the reach (with freshly charged batteries) very impressive even with the Better Beamer.