Who doesn't love Guinea Pigs - they're delicious! LOL JK, they are way too cute.

Here's a collection of tubes to keep the pigs (or other small critters) entertained. Two different sizes are included, 115mm and 130mm. Scale them to fit your particular critter size.

My pigs are rather skeeered (scared), and they wouldn't go in the 115mm tubes at first, so I made the larger tubes as trainers. Now they are used to them and freely go through them (when they haven't nosed them upside down haha).

Freecad file included, modify to suit your needs.

{edit Apr29 2021} I didn't expect such interest in this! I'd love to see your makes, post them up! Are there other shapes you'd want me to make?