Review (3/5): Great idea
... and works fairly well. It stays on your head better than those satiny/silky types. It is heavy though. It has a built in flap that comes down to cover your eyes if you are used to sleeping with a sleep mask. I am, so I was interested in that feature. However, this will be a winter item for me, only if the room I'm sleeping in is cool enough. I get hot very easily and found this restricting and yes, hot! I prefer a lightweight sleep mask, so I felt a bit smothered by this, lol.
It stretches but has to be broken in as it is quite tight in the first few uses and hard to get long hair into it. I have not tried washing it yet, but maybe that will take some of the stiffness out of it.
It does keep your hair in place though and if this is your main interest do try it.