Pia, these are adorable and I am sure your girls adore them.
They love them as they can have them in colors and with designs of their own choice. And as small as they are, they love to have something that is only theirs and nobody else has got.
They are very easy to make. We have lots and lots of them.
I always make them in cotton-fleece instead of polar-fleece, because it is much more protective to the childrens ears. It safes them from inflammation of the middle ear. I think partly because - as my girls puts it - they are so nice to wear not to warm not to cold. And because they have so many different, they put on the one they like most that particular day.
Now that's sensible head covering will keep a head lovely & warm, as well as protected