Tim Shoppa wrote in
oups.com:

In my garage, from some past project, I found some thin-wall white
(probably PVC) plastic tube. About the same diameter and a little less
thickness as 1/2" copper pipe, but plastic.

It was way way way thinner wall than schedule 40 PVC pipe. So thin
that it's somewhat transluscent.

What is this stuff called and what is it supposed to be used for?


Everybody else is guessing so what the heck.

From your past project or just appeared? Got central vac? Don't they run
some kind of plastic pipe in new construction, suck some string through
then pull wires? Really a WAG.