The R4 DS (R4DS) v2 allows for more than just gaming. Now you can use watch movies, play music, browse pictures, read E-Books and more on your Nintendo DS and DS Lite! This is NOT a cheap R4DS copy - beware of unofficial cut-price clones!
The R4DS is a slot 1 device (which requires no passcard) from the famous producer R4 Team. It uses a Micro SD card for low cost and high capacity while fitting nicely in your DS/DS Lite.