Secure Digital (SD) is a flash memory (non-volatile) memory card format used in the Wii, Nintendo 3DS, Nintendo DSi, Nintendo DSi XL, and Nintendo Switch for data storage. A 2GB Toshiba SD card came equipped with the original Nintendo 3DS. Later 3DS consoles would have a 4GB SD Card included instead and New 3DS consoles would have a 4GB Micro SD Card. Micro SD Cards up to 2 Terabytes can be used with the Nintendo Switch.
Stores additional downloads from the Wii Virtual Console and WiiWare libraries.
In the Photo Channel, you can insert a SD card from a digital camera, DSi, or 3DS. you can do various things, including puzzle games with videos, slideshows with photos, etc.