Love this headboard! 
However, we have a twin-Full size metal bed frame and it does not fit with it although it says will fit Full/Queen size bed frame above. I think it really it is really Queen only because of the width of the legs of the headboard. 
We were still able to secure it with 2 of the 4 screws and it is stable, but we do plan to get a wider bed frame so that it is more secure to this headboard at a later time.