Not to be mounted on the rail. Only when these 45mm rail has strength.

I needed for my Easter holiday departures and roof racks.
So quickly in Amazon an immediate deliverable carrier system order.
This was then delivered on time.
But then came the sobering realization that this system is as it is useless.
In the manual is, quick installation, rail thickness 25mm.
Wonderful, my Passat has a railing with a thickness of 25mm.
But then the disappointment, the retaining clips could only be to min. 45mm screw together. From 25mm because, as in the instructions. Me9ines knowledge, there is no rail with a thickness of 45mm.
After 2 hours unsuccessfully trying I had to abort the installation attempt. Also neighborly help attempts failed.
But since I now absolutely needed a roof rack, otherwise I would have to Sch. returned, I had to completely disassemble the 4 shots. Notching Plastic shots extent and remodel until they could be screwed together to the required 25mm.
At 10am I started the assembly and by 14am I was finished with remodeling and refitting.
Since you can at least only awarded one star, even one star.
There are certainly better roof rack.