SD and SDHD Cards
The SD and SDHD cards are the exact same size at 32 mm by 24 mm by 2.1 mm. They weigh approximately 2 grams. Nine pins connect the cards to the SD card reader. An SD card can contain up to 2 GB of data. An SDHD card can contain up to 32 GB of data.
Compatibility with Older Wii Software
The oldest Wii software can read only SD cards that contain 2 GB of data or less.
Wii 4.0 or Higher
Wiis that have software updates higher than 4.0 can read SD cards and SDHD cards that have up to 32 GB of data.
Licensed SD Cards
Nintendo has licensed SanDisk and Bensussen Deutsch &Associates Inc. to make SD cards with its official Nintendo Seal of Approval. Although other brands of cards may not carry this seal, they should still work in the Wii.