I created a whole new model since the original wouldn't work for me, but this is basically a copy of JammerX19's idea but for a different RAM 1500, with different spacing on the headrest posts. Mine are 11mm posts spaced 15cm on center.
Thanks to JammerX19 for the idea - I never had a good way to mount my remote speaker and since my radio sits under the driver's seat, the built in speaker was always difficult to hear even at max volume. Now I have the volume at a reasonable level and can hear it even over the stereo.
Printed in PETG. My remote speaker used an M4 screw, so the mounting hole is sized accordingly.
The author remixed this model.