What's this object?

Today something completely different. No cool photo, but a real quiz! Yeah!

My girlf got this object as a present from her hairdresser, because they are in business for 10 years. She asked me to guess what this object is. I examined it for minutes and gave up. I needed the "manual" to understand what it is.

Do you know what it is?

You can fold the object, so it becomes like a coin with the metal strip around it. The round part has at one side white plastic and at the other side some soft black material as shown on the picture. You can turn the round part freely.

I will give you the answer coming weekend with another photo. Let's see who is smarter than me and knows what it is ;-)