Great diffuser
Bought this for my RUSK hair dryer - fits perfectly, and as tight as when I first put it on. Not sure why people have problems with it.  It's a pretty straightforward process to attach this diffuser and it has remained solid with consistent use for 3 months.  For me, it's too large to travel with but it's great for home use.  Seems to be engineered and manufactured well.  Highly recommend.
Rating: 5 stars