Don’t know what this really does but my wife was happy to get it.

I use it at the gym super practical, but consider it does not fit old hair dryers.

So...this diffuser fits on my dryer perfectly and the fact that it folds is amazing. However, the air is blocked throughout the entire middle portion of the diffuser so the air only comes out of the perimeter of the diffuser. Extremely disappointing.

I have curly hair. No matter what type of diffuser I use my hair comes out frizzy ... until now! This little beauty works great and no frizz. The collapse is just a bonus.

I have short curly hair and spent the first few decades of my life working against the curl before finally learning to work with it. It needs lots of moisturizing and some specialty products. The final piece to the puzzle is air drying or gently diffused drying. The diffuser that came with my dryer had too large of holes caused frizz.