I picked up the rbt smoke xl8rs (long and short) for my Mi and the long one certainly cools things down. Haven’t tried the short one yet. It’s curious but for me, DDave’s difuser works better. Just like my F2 with the standard mouthpiece doesn’t irritate me. Getting the vapor dispersed well before inhalation seems to be what works for me. Then again, h2o does the trick too! I’ve never been a water person due to the fact that I generally have to vape on the fly. But my recent issues with lung irritation are making me adjust. I’m not complaining. A nice hit on a Mi through a D-20 provides a nice and lasting experience.