Personally I bought three copies of the products. When I received, I was skeptical. Note: do not forget to order a micro SD card to view this unit. It is true qu''il no doc, but the use is simple. You insert the micro SD into the device, without forcing. If it does not fit change direction. Once the card is inserted connecting the MP3 to your computer, you see the mp3 as a USB key. Personally, I put 4GB SDHC card but you can go up to 8GB. Then you transfer your MP3 files on it. The transfer is quite slow. Personally, 2GB in 10 minutes, but after it's done. The first time, leave the device connected to the computer 3 to 4 hours to charge it. To test I plugged in HP amplified fixed computer. Just put it on "on" and it begins playing the first file. Play the pause button, volume, track skip forward and back functions. I was surprised by the quality of this tiny device for now tested on my HP. The sound is very correct. To see with the supplied headphones or other helmets. Unlike all the negative reviews, personal, for the price it suits me well. By cons I did not recoil over time, as tested for the first time that day.