About this 3D model

My friends and I are taking some Padel lessons, and we'd have to pick up 50 or so balls by hand losing a lot of time. I bought a whole 20' length of 3" drainage PVC, so 6 of these devices came out of the project. Each 1m length can fit 16 to 17 balls inside it. I printed the top in PETG and the bottom with TPU, I don't know if the bottom will work with stiffer filament. Uploaded a new version with tougher upper cap.