Protection function:
The back is protected against scratches and the shell therefore fulfills its purpose. Positive side effect: The camera is no longer, and is therefore also somewhat protected with cover than without.
Processing:
0.3mm are already really thin. The case is easy and the fit is perfect.
Conclusion:
Strong buy recommendation for people who want to preserve the back of the iPhone from scratches. The front of the iPhone is made of extra-resistant glass, therefore I have the enclosed foil inappropriate.