Careful, this could cost you a lot of money...,
This review is from: for iPhone 5 Nano SIM Card Adapter Black (Wireless Phone Accessory)
I have used this product to fit my NanoSIM inside the MicroSIM slot of a Samsung Galaxy S IV. As the fit is not perfect, there is a high risk of damaging the very delicate connectors of the SIM reader inside the phone when taking out the SIM... as I did.
It's much better to pay the (usually small) fee of your mobile operator to get a MicroSIM duplicate than risk a costly reparation of your phone for using these kind of adapters. And this is not a problem with this particular model, it's a common problem with all SIM adapters.