A holder for two large (ø ~92mm ) shampoo and conditioner bottles to be squeezed onto two 12mm pipes
I used adaptive, but 0.2 would work fine
I added some rubber (purple parts) to prevent sliding on the pipes. I also added some m3 threaded brass inserts in the back plate by heating them up with a soldering iron and pressing them into the holes from the back. I then stuck the back plate behind the pipes and screwed the holder body into the back plate.