Universal rubber band smartphone holder for camera tripod mounting

This is a very simple universal smartphone holder so that you can mount your phone onto a camera tripod or other camera holder using the industry standard 1/4 20 camera mounting screw. You just need a rubber band, and you can adjust the grip by twisting the band appropriately. I have tried both tapping straight onto the plastic and also gluing a 1/4 20 threaded insert onto the adapter and both solutions work equally well.