Neato! MAKE parts from volume 03 hits eBay! Yes, This IS what you are looking for! As Seen in “Make” the Magazine. These are the Barrels for the Launchers. In the picture you can see part of the length you are getting. The $2 bill is laying on the inside of the pipe to show the transparency, The Color is Blueish. Link.
TRANSPARENT PVC Clear for potato cannon