Its a seatbelt guide that mounts to the tonneau cover bolt.
You will need a m6 30mm long bolt, the original is too short.
Recommend to print from PCTG ASA or Nylon. However i have broken some ASA seatbelt mount designs in the past, its a lot more prone to break. PCTG / Nylon is alot more forgiving in terms of bending/breaking.
Purpose of this seatbelt guide is to bring down and out the seatbelt position after placing a very low seat in the car. This will stop the seatbelt from cutting into your neck. It should bend/break in case of an accident, but obviously has never been tested in crash environment.
Use at own risk.
The author marked this model as their own original creation.