Disclaimer:
The part is a prototype and not tested and has no TÜV.
Operation is not permitted on German roads.
I assume no liability.
The APR Airfilter wich the adapter is designed for is this one:
https://goapr.de/car-configurator?carId=01914a67ae0978d0b2ba0d5f1b0ad9a8
The author marked this model as their own original creation.