Firstly, we all know how loud open downstems can be, especially on the regal..
This diffuser, was like putting a silencer on a .50 cal. Like, why wouldn't you ;-) it was quiet what seemed like a whisper. I HIGHLY recommend for those pipes that don't have a diffuser.
As well, it comes with 3 attachments that fit snug on whatever diameter sized downstem your hookah comes with, and the fact that it's silicone, means its safe to clean, and lasts long.