I have a small, one footer that i really like. my friend has a larger one with a diffuser and i really like how it fills with smoke. It starts really thick and creamy at the bottom and really slowly creeps its way to the top. Mine just fills evenly throughout the whole bong. My friends does have a diffuser, mine does not. Would that make a difference? if so, im not even sure if mine could fit a diffuser. it has a small glass down stem thats it.