We ordered these and used them in my Galaxy Note 2 and my wife's Razr M. After a few months we noticed that they would cause the phone to freeze up. The phones would start showing that it was mounting and unmounting the SD card early on but toward the end they just froze up the phone. Once we trashed the cards, the phones worked fine. We bought a different brand and no trouble since. I don't know why these red & gray ones have issues but stay away from them.