I bought this extra memory for my Samsung Galaxy S4.  I wish I had known when I bought my phone that Android changed its memory management technique between Gingerbread and Jelly Bean!  Verizon sold me a 16GB Samsung S4.  I didn't do much research since my old phone broke and I was about to leave on a business trip the next day.  Come to find out, there are 32 and 64GB versions of the Galaxy S4!  I never asked Verizon if they even carried different versions.  Well, I figured that wouldn't be a problem... I'll just put in a 64GB Micro SD (TF) Card and I'll be all set.  Unfortunately you can no longer transfer Apps to the Micro SD Card.  Some apps can store data on the SD Card but there is no longer the ability to "Move to SD."  Since I travel internationally, I use a lot of GPS mapping software and would like to download multiple Gigs of map data for offline mapping.  As of now, I can only download this to my phone's 16GB memory, and not to this 64GB memory card!  Pictures (except for burst photos), videos and music can all be put on the 64GB SD card.  All that being said, this memory card works well, and is priced on par with all of the other comparable cards on the market.  If you've got the cash and need the space (for music, videos/movies and/or pictures--just not apps) then I recommend picking one of these up.