The pots are cut from 4" PVC and capped. In my oppinion it's better than the online one because its much stronger and more level. The other version calls for 2 liter bottles cut, which is incredibly weak and they flex out of shape. Also, with mine, the part they never tell u is that once water flows through, the entire PVC frame will flex and create minor cracks at the connections which will leak like crazy, mine compensates for that with no leaking and and even flow of water throughout the PVC. The major modification takes place where the pots are connected... I never took pictures of how I did it, but it's MUCH better than the way the online guide said, (which was to screw in the 2 liter bottles to a threaded connector). Mine doesn't leak, has an even distribution of water flow, and I built that custom stand to perfectly fit the system which makes it all the better. If you're still wondering what exactly I did to modify it, I'll try to take some pics of inside the pots to show you, it's hard to describe because I don't know the names of the pieces I used inside.