"Can someone explain (like I'm 5) which r4 card will work in my Dsi?"に関する回答If you're looking for a flashcart I'd recommend this one: https://m.newegg.com/products/9SIAGXY914... I use it with my 3ds all the time. Micro SD cards you can find just about anywhere. You shouldn't need more than 8-16GB for the R4 as DS titles are fairly small.