I used it for my Galaxy S4 for a good 6 months without any problems. And just today.. It's died. Won't work at all, can't recover any files, can't even format it to re-use it. It is now a worthless tiny chip... Thanks, Kingston. Won't be using this product again. Any one else who plans on using this for a phone, especially a Samsung, I would recommend you buy Samsung's brand for the SD card. I should have done that from the start, but I wasn't even aware they made an SD card brand at the time. (I should have known.. Samsung makes everything!)