bubbler by Kevin [created on 3DTin] scale down the stl so that the outer diameter of the tube is the inner diameter of the tubing to be used print one part (you can print both of possible) repeat for other part if necessary fill bottom half way with water glue, melt, or (if you have a 3Doodler) meld the parts together with the tubing up tube that goes down is the input tube from top is output