I have seen a lot of people use these but I have no idea how to go about making one, they call them "uzi's" for whatever reason. I tried using someone's "uzi" once and it worked pretty well, but not much better than a normal glass stem and brillo pipe like I would normally use. The reason I really like standard glass stem and chore pipes is that can re-smoke the residue by simply pushing the brillo to the other side of the pipe when it dries leaving behind a golden brown colored flaked up, waxy/oily like substance. Sometimes the residue gets me higher than the crack itself. I have also seen someone who used one of those homemade "uzi" liquor bottle pipes, after smoking quite a bit of crack out of it, take some isopropyl alcohol and pour it in the bottle, shake it around to get all the residue mixed with the alcohol, then dump out the alcohol with the residue in it on a pyrex glass plate and light it on fire. They let all the alcohol evaporate so there was no liquid left and it dried up, creating a grayish colored slab from all the crack residue that was a huge portion of re-rocked crack and able to be smoked just like a normal piece. It was very strong too, I tried smoking some. It was super cool, but I would be a little nervous to try this myself as I wouldn't want to light my house on fire by accident or screw it up in the process and waste it all. This person was a veteran crack smoker who had been smoking since crack came out so they were very experienced and knew every trick there is to smoke crack and get the most out of it every way possible. I wish I knew how to make one of those for when my stems break down to like 1-2 inches and I cant afford a new stem and crack at the same time.