I have a freind with a double-bubbler bong. It was cool when it was new but there is one tube going up from the bottom bubble chamber doing a U turn into the second bubble chamber about 1/2" Diameter. That tube clogged solid w/ resin and now he can't clean it. Even the DR 420 or whatever wouldn't clear it out. So if you get a double bubble bong, make sure it comes apart or is easily cleaned.