[Percy's Mom]

I have a 6" PVC arch, but that is really quite huge. A 4" is fine unless your piggers are really big. Incidently, if you have cats, they like the PVC tubes too. I made the mistake of leaving mine in the family room before I got it upstairs and found my 12 year old cat in it with his head and front legs out one end and his tail and back legs out the other. I'm still waiting for him to do it again, so I can get a picture!
You might also want to do a search in the forums for PVC ramp. A couple members have cut tubes in half to make ramps to the second level of their cages.