This is a Holder for a Fairphone 4. I designed it to replace a holder I already had in my car that was too small for the fairphone, so there were parts, that I already had installed and reused. (Ball-joint and gooseneck) I included a stub balljoint with a throat od of 5mm that has a 2.5mm bore so you can screw a m3 bolt in there. The fit of the holder works great with my own bumper case, but I had a bigger one on there before and that still fit. The female part of the balljoint is fixed to the holder with 4 countersunk 10mm M3 screws. printing: If you want to use it in a car, use heat resistant filament with good layer adhesion. PETG might work, I used PCTG and it works great. Parts with threads @0.1 layer height, the rest@ 0.2mm. Annealed PLA might also work. Give it plenty of printing temp for better layer adhesion, especially the balljoint parts need it.