This is a model to store your Wireless Dongle with your T4 Pro wireless gaming controller. It slides into the connector on the front that would usually hold the phone mount. It allows the controller to still be charged while the mount is on. Should be printed standing up for most strength for the notches that hold it in. Dimensions for mounting locations were taken from the official phone mount.
WARNING: Dongle should fit snuggly and stay in with a friction fit, but not be so tight that you have to push hard to get it in. If you have to press it in, it may get stuck. There is a hole on the bottom so you can push it out if it does happen.
This was designed in SolveSpace, the open source parametric CAD software. I've included the native file if you decide to remix it for some other purpose.