It's a pretty wild concept yet extremely practical and it makes sense from Dane-Elec. Dane-Elec makes memory cards and card readers. An MP3 recorder and player is essentially a storage device that lets you transfer files from your computer and listen to them through a headphone. So the BU-MP3S-SD1024 zMate Plus SDCard Reader with 1GB SD Memory is essentially a card reader with a USB port for a computer connection and a headphone jack - with a slot for an SD memory card. In this case, a 1GB SD storage card is included. It can record and play MP3 and WMA files. 1GB memory can typically hold about 500 WMA/ 33hrs (64 kbps), 250 MP3/ 16hrs (at 128kbps). Need more capacity? There's no need to change the player. You have the ability to purchase more SD memory cards to store additional songs. This compact and modular system lets you organize your files with virtually unlimited storage! You can use it with a Windows PC or a Macintosh computer. It's an MP3 player that finally makes sense. Windows 2000/XP and Macintosh OSX compatible Convenient control MP3 and WMA file compatible May also be used to store data and image files for transfer to another computer or USB device MP3/WMA player with SD/MMC card slot also works as an SD/MMC card reader Runs off AAA battery (not included) Windows 2000, XP and Mac OSX compatible Dane-Elec 1 year warranty