Review (5/5): Works great!
This diffuser fits my Rusk W8less hair dryer perfectly. I have been using the Conair universal diffuser for years but it continually pops of the hair dryer. The Bio Ionic fits snug and does not pop off. My hair dries faster and my curls are better than before. Highly recommend. It's a little pricey, but should last years and years. It might not travel well because it is rather large. I use a collapsible diffuser for travel, but it does not work as well as the Bio Ionic.