a diffuser's a downstem, but instead of one large hole at the bottom there are many. As far as I know, ROORs have the most holes. The name diffuser is a term used in mechanics for displacement, I believe. I does make for a much smoother hit, but mine has never clogged.
graph Reviewed by graph on . RooR... (durability?) I'm thinking of buying a roor. I am finally getting a place where I'll be allowed to smoke inside (parents, then dorm, now finally an apartment)(FINALLY!). My only question about them is how durable are the different thicknesses? obviously a 7mm is going to hold up to the occasional bump or drop better than a 3.2mm one but 7 is so damn expensive I might not be able to work it into my budget. Who all has a roor, how thick is it and how durable have you found it to be? Rating: 5