Print both parts. Glue a 1/4" dowel or rod into the top part of the mount and slip it through the hole in the bottom part. Make the dowel long enough to fit your largest device with some room to spare so you don't get stuck. Add some weights to the bottom of the dowel (I used two large washers held on with wire, but anything could work). Secure the bottom to a wall or post using #6 wood screws. I also added rubberized tape to the grove in the bottom part to prevent slippage.