With a few parts. Like a broken downstem, gum container, bottle cap, plastic tubing, fluorescent light tubing, and some good ole' hot glue. Which btw is not toxic. Just wrap a little electric tape around the gum container ( its something they sell at wal-mart, its like plant a tree gum or something like that ) and if you stick it in the neck it should be air-tight. Then make a hole up top, and get some plastic tubing, i used flutes from the dollar tree. And bend it down like in my pic, insert broken downstem in the big end of the flute. Glue fluorescent light tube to bottle cap and make an air-tight, water-tight seal, if you dont then its a bitch to start over. Then make a hole some where near the bottom of the FL tube, Hot glue seal everything, and you now have a perc!
