What is this hair thing called?

Okay, there's this new hair clip type thing out. It's like a clip sort of like they can have bow designs and stuff but the difference is they don't have a clip or any type of thing to attach it to your hair, it just has this flat black square on the back and you just slide it on top of your hair and it stays. And just to be a little more specific no it's not bobbi pins, or barretes, or anything like that. I know I can't give a very good description but if anyone knows what I'm talking about please help me out. Thanks for any answers :)