The interface upgrade to have the Hardrock HR50 amplifier communicate with the Icom IC-705 allows the radio to communicate with the amp using the Icom tuner function. It adds an extra 3.5mm jack but the upgrade kit does not include a new end panel; the instructions call for the user drilling a hole or leaving the end of the enclosure open. I messed up drilling a hole so I made this :-)
The text in the print is a little hard to read but it labels the “tuner” jack and the “send/alc” jack for the appropriate connections to the radio. The .3mf file is set up for a 0.6 nozzle as was used for the print in the photo, so this could be improved with a smaller nozzle (I did use Arachne perimeters). I also include the Fusion 360 file.
The author marked this model as their own original creation.