I needed a tight receiver mount for a space-limited quadcopter build.. this was what I came up with. It is 8mm tall and and holds a de-pinned FRSKY receiver nicely. You can easily slot a corner for the smart-bus wire, and I've included a lid for people that have PDB's with errant pins underneath. 8mm hexagon standoffs press fit into the reliefs, and you can sandwich your receiver safely underneath your other electronics. Works great. I potted mine, but it'll be secure with or without glue/epoxy. The holes are slotted in the thin model to accommodate the different antenna PCB locations between the two receivers, but I will add the X4i receiver-specific model later. The D4R model is ready to go. Enjoy!