This Switch Joycon Adapter was designed by Semmel and posted over at Prusaprinters

This listing is for 1x Joycon Adapter which is available in a wide choice of colours.

These fit the Joycons perfectly and are extremely comfortable to hold, it can be very uncomfortable playing split screen holding the original controllers. These make it much more enjoyable. 

If you wish to print this yourself you can download the files directly from the creator https://www.printables.com/model/161938-joycon-controller-with-trigger-buttons-easy-print/files 

This work is licensed under a
Creative Commons (4.0 International License)