Summary

I wanted a knockbox that looks professional and is easy to clean, so I built one from a gastro container.
Printed the rod and container damper from TPU with minimum 5 walls, to provide proper stiffness. I drilled 4mm holes into the gastro container and fixed the rod with 2 pcs 4,5x35mm screws.
The box is printed from PLA+ with nearly stock settings from my Anycubic Kobra 3.