I put this into my SGS4 and while it worked, the phone occasionally said the card was damaged. I reboot and it's fine. I got tired of this and attempted to reformat it. Not only did it take forever - way longer than it should have, it also stopped half-way through formatting and died. Yup. It's completely dead. Neither my computer nor my phone even see it. It's supposedly a class 10, but it's way slow to transfer files to and from compared to my 32gb class 4 from the same manufacturer.