It doesn't work, don't buy it! [SEP] Worst invention ever!  This got returned to Amazon 30sec after trying it.  The attachment part has to be forcefully stretched over hair dryer nosel. it pops off a lot and the silicon gets so hot that you can't even try to put back on until it cools down .  The worst is that it collapses as you try to use it!  Seriously! It has no weight to the product so can't use on roots /scalp.  It's just completely worthless.