I bought a Brita-compatible filter cartridge from DM supermarket in Germany, which is more affordable than the original. However, it lacks the cross-shaped bump at the bottom that opens the valve inside the water tank.
To solve this issue, I designed and 3D printed a small adapter that fits into the bottom of the tank and presses the valve properly.

This part ensures water flow works correctly with non-original Brita filters.
It's small, easy to install, and printed in food-safe PLA, especially safe at low temperatures.

✅ Designed for compatibility with DM-sold Brita filters
✅ Ensures proper valve activation
✅ Food-safe PLA material
✅ Easy to install and remove