Following positive review from forum members, I purchased one of those space cosmonaut looking dryer, not the ION one, but one manufactured by a swiss company
But after a few trials, I have stopped using it.
1. Unlike my initial hope, the space under the cap is rather smaller than the professional hard hat dryer I use. In particular, no way to get a head full of 3 inches mag under the oft bonnet. You cannot get your head in and this is a pity, because it would have been easy to manage a detachable part somewhere
2. The drying is significantly slower than the hard hat
3. Even if it seems an improvement to be able to move (not really freely !) in a short radius, the look brings so many comments, that I cannot sustain seing myself in the mirror with that thing around my head. My husband, who is the kindest guy on earth for all what is related to hair care, clearly expressed his view that my natural drying place was under the hard hat and not under this space ship accessory.
We agreed however that I could use it during holiday travels as it is really a small volume box (less than the rollers themelves !).