precisely the right spare part

The supplier of the shower "Rain Pool" was no longer accessible, so I had to search the net for suitable spare parts and found it.
After some skepticism I was delighted to find that the waste is to be just right for my shower. The installation was easy. Perhaps the manufacturer should give the tip that with a self-shaped ring of Plastikfermit that distributes between the top of the shower tray and the bottom of the ride-on waste set up when tightening the fittings in all the bumps. Excess material is squeezed to the outside and can be cut off cleanly. The tightness is now guaranteed at 100%. Not all amateur plumbers know this. This tip I have from a professional.