I've got a phone that I use for the FPV view while flying. Some phones/tables these days have the volume buttons on the side. Also my phone has a case on it. When using the p3 controller I would have to take my phone out of its case and off set it's position in the clamp so the volume and power buttons weren't interfered with. Royal pain on the ***. I'm running a nexus 6. I came up with this. Works a treat.