i made one, it doesnt work that well cuz theres three holes where air can get in other than through the bowl, one is between teh bowl and the cap, inbetween the pen and the hole in the side, and anotherone between the cap and the tube thing. so basically it didnt work unless i wanted to spend the time to make it airtight which i didnt. so yea, cool idea and it looks sweet but didnt work well for me.