Easy print with no supports required. Brim or mouse ears a good idea. I printed with Sunlu PETG. Friction fit and doesn't fall off, plus is easy to remove. Choose large or small. Pictured is the small litter guard.
Edit: Added versions with top caps by request. Use at your own risk until I hear otherwise.
Added version with SSDD text.
The author marked this model as their own original creation.