I bought this to put in my Olympus PEN E-PM1 camera which takes a standard SD card. Therefore it must go into the adapter to be put into the camera.  Unfortunately there is something touchy about this. Sometimes I turn the camera on and get a card error. Sometimes I can pop the card out and back in and it'll work. This past weekend I couldn't get it to work at all.  I'm guessing it's the camera. Or maybe the adapter?  When I plugged the card and adapter into my computer to copy the pictures off, it worked perfectly. So I'm not sure what the problem is. I make sure to always carry a spare "normal" SD card with my camera in case this one stops working.