Many people are confused by the different versions that are available and what the differences are between them. The main difference between the Version 1 and 2 R4 DS cards is that v1 had a spring loaded Micro SD slot. These slots were found to be unreliable and as such were removed from the design of the R4 Revolution v2 cards. Both of these versions can only handle a maximum capacity of a 2GB Micro SD card. The R4 SDHC version which is the next generation can handle a maximum of 8GB Micro SD, enabling it to read the SDHC (Secure Digital High Capacity) format which is the format for almost all 4GB and upwards SD and Micro SD cards. It is important to note that all the different versions above do require different software, this is talked about in more detail on the R4 software download page.