People often get confused as to which size memory card they will need for their Blackberry 8820. The size MicroSD or MicroSDHC card that a person will need for their 8820 with the pen on what they will be using the card for. If you will be just using it to store documents, then smaller cards sizes up to 512 MB can do. If you need the extra memory on the phone to save movies, music, ring tones, videos and pictures, then you should consider getting one of the bigger capacity cards. These cards are often 1GB, 2GB, 4GB, 6GB, 8GB, 16GB and 32GB. Because memory card prices are constantly falling, it is always good to get the biggest possible card that fits within your budget.