Blind spot mirror holder - adjustable

I bought an old Prius for camping, which doesn't have blindspot detection or mirrors. I tried a few holders that I didn't like. They weren't sturdy enough. They drooped in the summer heat. So I made a beefed-up version of that and printed it from TPU. It didn't melt in the heat but it wasn't ideal. So I designed my own, and after several bad iterations, I ended up with this one. I printed it in PLA+. It is winter here, so I don't know if it will survive the heat of summer, but I think it should with its sturdy design and printed in PLA+. If not, I'll try it in PETG. It might even be thick enough that my TPU would work. 
Use PRUSA Slicer to orient the mounting bracket on the print plate with the opening of the slot downward, and it can be printed with NO SUPPORT. 
Buy some stick-on, 2", blindspot mirrors, stick them on, adjust as needed, and enjoy. 

Installation Notes:

In the photo with it installed on the liner trim, you can see that it just slips under the flexible trim piece. On the lower-right side of the mirror, you can see the inside edge of the driver's door and the bottom of the driver's window. Just above that, on the right side, you can see two black hinges on the garage door. Those are shown in the regular left-side-view mirror. That gives an idea of how much more you can see in these little mirrors. The shelf that is visible at the left edge of the mirror is about 90 degrees from my position in the driver's seat. When looking straight forward, I can see it in my peripheral vision. A vehicle in my blind spot fills a good portion of this little mirror. As you can see, unlike mirrors you stick on your existing mirror, that block a good portion of that mirror, this mirror blocks none of the normal mirror. 

Print Notes: 

In addition to rotating the base for printing without support, I chose “rear” seam alignment.

I also printed with 4 perimeters, 5 top layers, 4 bottom layers, and 50% infill for strength. 

When you press the ball into the socket, it takes some force, but be careful not to put pressure on the flange that goes inside the vehicle trim, as it can break (trust me). I held the base on the sides as I pressed the ball into its socket, and that worked well. Also, installing the base/socket on the door trim and THEN pressing the ball into the socket doesn't put much pressure on the flange and can work.